[PATCH v4] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[PATCH v4] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[AngeloGioacchino Del Regno]

DRM bridge drivers are now attaching their DSI device at probe time,
which requires us to register our DSI host in order to let the bridge
to probe: this recently started producing an endless -EPROBE_DEFER
loop on some machines that are using external bridges, like the
parade-ps8640, found on the ACER Chromebook R13.

Now that the DSI hosts/devices probe sequence is documented, we can
do adjustments to the mtk_dsi driver as to both fix now and make sure
to avoid this situation in the future: for this, following what is
documented in drm_bridge.c, move the mtk_dsi component_add() to the
mtk_dsi_ops.attach callback and delete it in the detach callback;
keeping in mind that we are registering a drm_bridge for our DSI,
which is only used/attached if the DSI Host is bound, it wouldn't
make sense to keep adding our bridge at probe time (as it would
be useless to have it if mtk_dsi_ops.attach() fails!), so also move
that one to the dsi host attach function (and remove it in detach).

Cc: <stable@vger.kernel.org> # 5.15.x
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>

---
 drivers/gpu/drm/mediatek/mtk_dsi.c | 167 +++++++++++++++--------------
 1 file changed, 84 insertions(+), 83 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index 5d90d2eb0019..bced4c7d668e 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -786,18 +786,101 @@ void mtk_dsi_ddp_stop(struct device *dev)
 	mtk_dsi_poweroff(dsi);
 }
 
+static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi)
+{
+	int ret;
+
+	ret = drm_simple_encoder_init(drm, &dsi->encoder,
+				      DRM_MODE_ENCODER_DSI);
+	if (ret) {
+		DRM_ERROR("Failed to encoder init to drm\n");
+		return ret;
+	}
+
+	dsi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
+
+	ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL,
+				DRM_BRIDGE_ATTACH_NO_CONNECTOR);
+	if (ret)
+		goto err_cleanup_encoder;
+
+	dsi->connector = drm_bridge_connector_init(drm, &dsi->encoder);
+	if (IS_ERR(dsi->connector)) {
+		DRM_ERROR("Unable to create bridge connector\n");
+		ret = PTR_ERR(dsi->connector);
+		goto err_cleanup_encoder;
+	}
+	drm_connector_attach_encoder(dsi->connector, &dsi->encoder);
+
+	return 0;
+
+err_cleanup_encoder:
+	drm_encoder_cleanup(&dsi->encoder);
+	return ret;
+}
+
+static int mtk_dsi_bind(struct device *dev, struct device *master, void *data)
+{
+	int ret;
+	struct drm_device *drm = data;
+	struct mtk_dsi *dsi = dev_get_drvdata(dev);
+
+	ret = mtk_dsi_encoder_init(drm, dsi);
+	if (ret)
+		return ret;
+
+	return device_reset_optional(dev);
+}
+
+static void mtk_dsi_unbind(struct device *dev, struct device *master,
+			   void *data)
+{
+	struct mtk_dsi *dsi = dev_get_drvdata(dev);
+
+	drm_encoder_cleanup(&dsi->encoder);
+}
+
+static const struct component_ops mtk_dsi_component_ops = {
+	.bind = mtk_dsi_bind,
+	.unbind = mtk_dsi_unbind,
+};
+
 static int mtk_dsi_host_attach(struct mipi_dsi_host *host,
 			       struct mipi_dsi_device *device)
 {
 	struct mtk_dsi *dsi = host_to_dsi(host);
+	struct device *dev = host->dev;
+	int ret;
 
 	dsi->lanes = device->lanes;
 	dsi->format = device->format;
 	dsi->mode_flags = device->mode_flags;
+	dsi->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0);
+	if (IS_ERR(dsi->next_bridge))
+		return PTR_ERR(dsi->next_bridge);
+
+	drm_bridge_add(&dsi->bridge);
+
+	ret = component_add(host->dev, &mtk_dsi_component_ops);
+	if (ret) {
+		DRM_ERROR("failed to add dsi_host component: %d\n", ret);
+		drm_bridge_remove(&dsi->bridge);
+		return ret;
+	}
 
 	return 0;
 }
 
+static int mtk_dsi_host_detach(struct mipi_dsi_host *host,
+			       struct mipi_dsi_device *device)
+{
+	struct mtk_dsi *dsi = host_to_dsi(host);
+
+	component_del(host->dev, &mtk_dsi_component_ops);
+	drm_bridge_remove(&dsi->bridge);
+	return 0;
+}
+
 static void mtk_dsi_wait_for_idle(struct mtk_dsi *dsi)
 {
 	int ret;
@@ -938,73 +1021,14 @@ static ssize_t mtk_dsi_host_transfer(struct mipi_dsi_host *host,
 
 static const struct mipi_dsi_host_ops mtk_dsi_ops = {
 	.attach = mtk_dsi_host_attach,
+	.detach = mtk_dsi_host_detach,
 	.transfer = mtk_dsi_host_transfer,
 };
 
-static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi)
-{
-	int ret;
-
-	ret = drm_simple_encoder_init(drm, &dsi->encoder,
-				      DRM_MODE_ENCODER_DSI);
-	if (ret) {
-		DRM_ERROR("Failed to encoder init to drm\n");
-		return ret;
-	}
-
-	dsi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
-
-	ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL,
-				DRM_BRIDGE_ATTACH_NO_CONNECTOR);
-	if (ret)
-		goto err_cleanup_encoder;
-
-	dsi->connector = drm_bridge_connector_init(drm, &dsi->encoder);
-	if (IS_ERR(dsi->connector)) {
-		DRM_ERROR("Unable to create bridge connector\n");
-		ret = PTR_ERR(dsi->connector);
-		goto err_cleanup_encoder;
-	}
-	drm_connector_attach_encoder(dsi->connector, &dsi->encoder);
-
-	return 0;
-
-err_cleanup_encoder:
-	drm_encoder_cleanup(&dsi->encoder);
-	return ret;
-}
-
-static int mtk_dsi_bind(struct device *dev, struct device *master, void *data)
-{
-	int ret;
-	struct drm_device *drm = data;
-	struct mtk_dsi *dsi = dev_get_drvdata(dev);
-
-	ret = mtk_dsi_encoder_init(drm, dsi);
-	if (ret)
-		return ret;
-
-	return device_reset_optional(dev);
-}
-
-static void mtk_dsi_unbind(struct device *dev, struct device *master,
-			   void *data)
-{
-	struct mtk_dsi *dsi = dev_get_drvdata(dev);
-
-	drm_encoder_cleanup(&dsi->encoder);
-}
-
-static const struct component_ops mtk_dsi_component_ops = {
-	.bind = mtk_dsi_bind,
-	.unbind = mtk_dsi_unbind,
-};
-
 static int mtk_dsi_probe(struct platform_device *pdev)
 {
 	struct mtk_dsi *dsi;
 	struct device *dev = &pdev->dev;
-	struct drm_panel *panel;
 	struct resource *regs;
 	int irq_num;
 	int ret;
@@ -1021,19 +1045,6 @@ static int mtk_dsi_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0,
-					  &panel, &dsi->next_bridge);
-	if (ret)
-		goto err_unregister_host;
-
-	if (panel) {
-		dsi->next_bridge = devm_drm_panel_bridge_add(dev, panel);
-		if (IS_ERR(dsi->next_bridge)) {
-			ret = PTR_ERR(dsi->next_bridge);
-			goto err_unregister_host;
-		}
-	}
-
 	dsi->driver_data = of_device_get_match_data(dev);
 
 	dsi->engine_clk = devm_clk_get(dev, "engine");
@@ -1098,14 +1109,6 @@ static int mtk_dsi_probe(struct platform_device *pdev)
 	dsi->bridge.of_node = dev->of_node;
 	dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
 
-	drm_bridge_add(&dsi->bridge);
-
-	ret = component_add(&pdev->dev, &mtk_dsi_component_ops);
-	if (ret) {
-		dev_err(&pdev->dev, "failed to add component: %d\n", ret);
-		goto err_unregister_host;
-	}
-
 	return 0;
 
 err_unregister_host:
@@ -1118,8 +1121,6 @@ static int mtk_dsi_remove(struct platform_device *pdev)
 	struct mtk_dsi *dsi = platform_get_drvdata(pdev);
 
 	mtk_output_dsi_disable(dsi);
-	drm_bridge_remove(&dsi->bridge);
-	component_del(&pdev->dev, &mtk_dsi_component_ops);
 	mipi_dsi_host_unregister(&dsi->host);
 
 	return 0;
-- 
2.33.1

[PATCH v4] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[AngeloGioacchino Del Regno]

DRM bridge drivers are now attaching their DSI device at probe time,
which requires us to register our DSI host in order to let the bridge
to probe: this recently started producing an endless -EPROBE_DEFER
loop on some machines that are using external bridges, like the
parade-ps8640, found on the ACER Chromebook R13.

Now that the DSI hosts/devices probe sequence is documented, we can
do adjustments to the mtk_dsi driver as to both fix now and make sure
to avoid this situation in the future: for this, following what is
documented in drm_bridge.c, move the mtk_dsi component_add() to the
mtk_dsi_ops.attach callback and delete it in the detach callback;
keeping in mind that we are registering a drm_bridge for our DSI,
which is only used/attached if the DSI Host is bound, it wouldn't
make sense to keep adding our bridge at probe time (as it would
be useless to have it if mtk_dsi_ops.attach() fails!), so also move
that one to the dsi host attach function (and remove it in detach).

Cc: <stable@vger.kernel.org> # 5.15.x
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>

---
 drivers/gpu/drm/mediatek/mtk_dsi.c | 167 +++++++++++++++--------------
 1 file changed, 84 insertions(+), 83 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index 5d90d2eb0019..bced4c7d668e 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -786,18 +786,101 @@ void mtk_dsi_ddp_stop(struct device *dev)
 	mtk_dsi_poweroff(dsi);
 }
 
+static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi)
+{
+	int ret;
+
+	ret = drm_simple_encoder_init(drm, &dsi->encoder,
+				      DRM_MODE_ENCODER_DSI);
+	if (ret) {
+		DRM_ERROR("Failed to encoder init to drm\n");
+		return ret;
+	}
+
+	dsi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
+
+	ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL,
+				DRM_BRIDGE_ATTACH_NO_CONNECTOR);
+	if (ret)
+		goto err_cleanup_encoder;
+
+	dsi->connector = drm_bridge_connector_init(drm, &dsi->encoder);
+	if (IS_ERR(dsi->connector)) {
+		DRM_ERROR("Unable to create bridge connector\n");
+		ret = PTR_ERR(dsi->connector);
+		goto err_cleanup_encoder;
+	}
+	drm_connector_attach_encoder(dsi->connector, &dsi->encoder);
+
+	return 0;
+
+err_cleanup_encoder:
+	drm_encoder_cleanup(&dsi->encoder);
+	return ret;
+}
+
+static int mtk_dsi_bind(struct device *dev, struct device *master, void *data)
+{
+	int ret;
+	struct drm_device *drm = data;
+	struct mtk_dsi *dsi = dev_get_drvdata(dev);
+
+	ret = mtk_dsi_encoder_init(drm, dsi);
+	if (ret)
+		return ret;
+
+	return device_reset_optional(dev);
+}
+
+static void mtk_dsi_unbind(struct device *dev, struct device *master,
+			   void *data)
+{
+	struct mtk_dsi *dsi = dev_get_drvdata(dev);
+
+	drm_encoder_cleanup(&dsi->encoder);
+}
+
+static const struct component_ops mtk_dsi_component_ops = {
+	.bind = mtk_dsi_bind,
+	.unbind = mtk_dsi_unbind,
+};
+
 static int mtk_dsi_host_attach(struct mipi_dsi_host *host,
 			       struct mipi_dsi_device *device)
 {
 	struct mtk_dsi *dsi = host_to_dsi(host);
+	struct device *dev = host->dev;
+	int ret;
 
 	dsi->lanes = device->lanes;
 	dsi->format = device->format;
 	dsi->mode_flags = device->mode_flags;
+	dsi->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0);
+	if (IS_ERR(dsi->next_bridge))
+		return PTR_ERR(dsi->next_bridge);
+
+	drm_bridge_add(&dsi->bridge);
+
+	ret = component_add(host->dev, &mtk_dsi_component_ops);
+	if (ret) {
+		DRM_ERROR("failed to add dsi_host component: %d\n", ret);
+		drm_bridge_remove(&dsi->bridge);
+		return ret;
+	}
 
 	return 0;
 }
 
+static int mtk_dsi_host_detach(struct mipi_dsi_host *host,
+			       struct mipi_dsi_device *device)
+{
+	struct mtk_dsi *dsi = host_to_dsi(host);
+
+	component_del(host->dev, &mtk_dsi_component_ops);
+	drm_bridge_remove(&dsi->bridge);
+	return 0;
+}
+
 static void mtk_dsi_wait_for_idle(struct mtk_dsi *dsi)
 {
 	int ret;
@@ -938,73 +1021,14 @@ static ssize_t mtk_dsi_host_transfer(struct mipi_dsi_host *host,
 
 static const struct mipi_dsi_host_ops mtk_dsi_ops = {
 	.attach = mtk_dsi_host_attach,
+	.detach = mtk_dsi_host_detach,
 	.transfer = mtk_dsi_host_transfer,
 };
 
-static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi)
-{
-	int ret;
-
-	ret = drm_simple_encoder_init(drm, &dsi->encoder,
-				      DRM_MODE_ENCODER_DSI);
-	if (ret) {
-		DRM_ERROR("Failed to encoder init to drm\n");
-		return ret;
-	}
-
-	dsi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
-
-	ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL,
-				DRM_BRIDGE_ATTACH_NO_CONNECTOR);
-	if (ret)
-		goto err_cleanup_encoder;
-
-	dsi->connector = drm_bridge_connector_init(drm, &dsi->encoder);
-	if (IS_ERR(dsi->connector)) {
-		DRM_ERROR("Unable to create bridge connector\n");
-		ret = PTR_ERR(dsi->connector);
-		goto err_cleanup_encoder;
-	}
-	drm_connector_attach_encoder(dsi->connector, &dsi->encoder);
-
-	return 0;
-
-err_cleanup_encoder:
-	drm_encoder_cleanup(&dsi->encoder);
-	return ret;
-}
-
-static int mtk_dsi_bind(struct device *dev, struct device *master, void *data)
-{
-	int ret;
-	struct drm_device *drm = data;
-	struct mtk_dsi *dsi = dev_get_drvdata(dev);
-
-	ret = mtk_dsi_encoder_init(drm, dsi);
-	if (ret)
-		return ret;
-
-	return device_reset_optional(dev);
-}
-
-static void mtk_dsi_unbind(struct device *dev, struct device *master,
-			   void *data)
-{
-	struct mtk_dsi *dsi = dev_get_drvdata(dev);
-
-	drm_encoder_cleanup(&dsi->encoder);
-}
-
-static const struct component_ops mtk_dsi_component_ops = {
-	.bind = mtk_dsi_bind,
-	.unbind = mtk_dsi_unbind,
-};
-
 static int mtk_dsi_probe(struct platform_device *pdev)
 {
 	struct mtk_dsi *dsi;
 	struct device *dev = &pdev->dev;
-	struct drm_panel *panel;
 	struct resource *regs;
 	int irq_num;
 	int ret;
@@ -1021,19 +1045,6 @@ static int mtk_dsi_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0,
-					  &panel, &dsi->next_bridge);
-	if (ret)
-		goto err_unregister_host;
-
-	if (panel) {
-		dsi->next_bridge = devm_drm_panel_bridge_add(dev, panel);
-		if (IS_ERR(dsi->next_bridge)) {
-			ret = PTR_ERR(dsi->next_bridge);
-			goto err_unregister_host;
-		}
-	}
-
 	dsi->driver_data = of_device_get_match_data(dev);
 
 	dsi->engine_clk = devm_clk_get(dev, "engine");
@@ -1098,14 +1109,6 @@ static int mtk_dsi_probe(struct platform_device *pdev)
 	dsi->bridge.of_node = dev->of_node;
 	dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
 
-	drm_bridge_add(&dsi->bridge);
-
-	ret = component_add(&pdev->dev, &mtk_dsi_component_ops);
-	if (ret) {
-		dev_err(&pdev->dev, "failed to add component: %d\n", ret);
-		goto err_unregister_host;
-	}
-
 	return 0;
 
 err_unregister_host:
@@ -1118,8 +1121,6 @@ static int mtk_dsi_remove(struct platform_device *pdev)
 	struct mtk_dsi *dsi = platform_get_drvdata(pdev);
 
 	mtk_output_dsi_disable(dsi);
-	drm_bridge_remove(&dsi->bridge);
-	component_del(&pdev->dev, &mtk_dsi_component_ops);
 	mipi_dsi_host_unregister(&dsi->host);
 
 	return 0;
-- 
2.33.1


_______________________________________________
Linux-mediatek mailing list
Linux-mediatek@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-mediatek

[PATCH v4] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[AngeloGioacchino Del Regno]

DRM bridge drivers are now attaching their DSI device at probe time,
which requires us to register our DSI host in order to let the bridge
to probe: this recently started producing an endless -EPROBE_DEFER
loop on some machines that are using external bridges, like the
parade-ps8640, found on the ACER Chromebook R13.

Now that the DSI hosts/devices probe sequence is documented, we can
do adjustments to the mtk_dsi driver as to both fix now and make sure
to avoid this situation in the future: for this, following what is
documented in drm_bridge.c, move the mtk_dsi component_add() to the
mtk_dsi_ops.attach callback and delete it in the detach callback;
keeping in mind that we are registering a drm_bridge for our DSI,
which is only used/attached if the DSI Host is bound, it wouldn't
make sense to keep adding our bridge at probe time (as it would
be useless to have it if mtk_dsi_ops.attach() fails!), so also move
that one to the dsi host attach function (and remove it in detach).

Cc: <stable@vger.kernel.org> # 5.15.x
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>

---
 drivers/gpu/drm/mediatek/mtk_dsi.c | 167 +++++++++++++++--------------
 1 file changed, 84 insertions(+), 83 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index 5d90d2eb0019..bced4c7d668e 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -786,18 +786,101 @@ void mtk_dsi_ddp_stop(struct device *dev)
 	mtk_dsi_poweroff(dsi);
 }
 
+static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi)
+{
+	int ret;
+
+	ret = drm_simple_encoder_init(drm, &dsi->encoder,
+				      DRM_MODE_ENCODER_DSI);
+	if (ret) {
+		DRM_ERROR("Failed to encoder init to drm\n");
+		return ret;
+	}
+
+	dsi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
+
+	ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL,
+				DRM_BRIDGE_ATTACH_NO_CONNECTOR);
+	if (ret)
+		goto err_cleanup_encoder;
+
+	dsi->connector = drm_bridge_connector_init(drm, &dsi->encoder);
+	if (IS_ERR(dsi->connector)) {
+		DRM_ERROR("Unable to create bridge connector\n");
+		ret = PTR_ERR(dsi->connector);
+		goto err_cleanup_encoder;
+	}
+	drm_connector_attach_encoder(dsi->connector, &dsi->encoder);
+
+	return 0;
+
+err_cleanup_encoder:
+	drm_encoder_cleanup(&dsi->encoder);
+	return ret;
+}
+
+static int mtk_dsi_bind(struct device *dev, struct device *master, void *data)
+{
+	int ret;
+	struct drm_device *drm = data;
+	struct mtk_dsi *dsi = dev_get_drvdata(dev);
+
+	ret = mtk_dsi_encoder_init(drm, dsi);
+	if (ret)
+		return ret;
+
+	return device_reset_optional(dev);
+}
+
+static void mtk_dsi_unbind(struct device *dev, struct device *master,
+			   void *data)
+{
+	struct mtk_dsi *dsi = dev_get_drvdata(dev);
+
+	drm_encoder_cleanup(&dsi->encoder);
+}
+
+static const struct component_ops mtk_dsi_component_ops = {
+	.bind = mtk_dsi_bind,
+	.unbind = mtk_dsi_unbind,
+};
+
 static int mtk_dsi_host_attach(struct mipi_dsi_host *host,
 			       struct mipi_dsi_device *device)
 {
 	struct mtk_dsi *dsi = host_to_dsi(host);
+	struct device *dev = host->dev;
+	int ret;
 
 	dsi->lanes = device->lanes;
 	dsi->format = device->format;
 	dsi->mode_flags = device->mode_flags;
+	dsi->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0);
+	if (IS_ERR(dsi->next_bridge))
+		return PTR_ERR(dsi->next_bridge);
+
+	drm_bridge_add(&dsi->bridge);
+
+	ret = component_add(host->dev, &mtk_dsi_component_ops);
+	if (ret) {
+		DRM_ERROR("failed to add dsi_host component: %d\n", ret);
+		drm_bridge_remove(&dsi->bridge);
+		return ret;
+	}
 
 	return 0;
 }
 
+static int mtk_dsi_host_detach(struct mipi_dsi_host *host,
+			       struct mipi_dsi_device *device)
+{
+	struct mtk_dsi *dsi = host_to_dsi(host);
+
+	component_del(host->dev, &mtk_dsi_component_ops);
+	drm_bridge_remove(&dsi->bridge);
+	return 0;
+}
+
 static void mtk_dsi_wait_for_idle(struct mtk_dsi *dsi)
 {
 	int ret;
@@ -938,73 +1021,14 @@ static ssize_t mtk_dsi_host_transfer(struct mipi_dsi_host *host,
 
 static const struct mipi_dsi_host_ops mtk_dsi_ops = {
 	.attach = mtk_dsi_host_attach,
+	.detach = mtk_dsi_host_detach,
 	.transfer = mtk_dsi_host_transfer,
 };
 
-static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi)
-{
-	int ret;
-
-	ret = drm_simple_encoder_init(drm, &dsi->encoder,
-				      DRM_MODE_ENCODER_DSI);
-	if (ret) {
-		DRM_ERROR("Failed to encoder init to drm\n");
-		return ret;
-	}
-
-	dsi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
-
-	ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL,
-				DRM_BRIDGE_ATTACH_NO_CONNECTOR);
-	if (ret)
-		goto err_cleanup_encoder;
-
-	dsi->connector = drm_bridge_connector_init(drm, &dsi->encoder);
-	if (IS_ERR(dsi->connector)) {
-		DRM_ERROR("Unable to create bridge connector\n");
-		ret = PTR_ERR(dsi->connector);
-		goto err_cleanup_encoder;
-	}
-	drm_connector_attach_encoder(dsi->connector, &dsi->encoder);
-
-	return 0;
-
-err_cleanup_encoder:
-	drm_encoder_cleanup(&dsi->encoder);
-	return ret;
-}
-
-static int mtk_dsi_bind(struct device *dev, struct device *master, void *data)
-{
-	int ret;
-	struct drm_device *drm = data;
-	struct mtk_dsi *dsi = dev_get_drvdata(dev);
-
-	ret = mtk_dsi_encoder_init(drm, dsi);
-	if (ret)
-		return ret;
-
-	return device_reset_optional(dev);
-}
-
-static void mtk_dsi_unbind(struct device *dev, struct device *master,
-			   void *data)
-{
-	struct mtk_dsi *dsi = dev_get_drvdata(dev);
-
-	drm_encoder_cleanup(&dsi->encoder);
-}
-
-static const struct component_ops mtk_dsi_component_ops = {
-	.bind = mtk_dsi_bind,
-	.unbind = mtk_dsi_unbind,
-};
-
 static int mtk_dsi_probe(struct platform_device *pdev)
 {
 	struct mtk_dsi *dsi;
 	struct device *dev = &pdev->dev;
-	struct drm_panel *panel;
 	struct resource *regs;
 	int irq_num;
 	int ret;
@@ -1021,19 +1045,6 @@ static int mtk_dsi_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0,
-					  &panel, &dsi->next_bridge);
-	if (ret)
-		goto err_unregister_host;
-
-	if (panel) {
-		dsi->next_bridge = devm_drm_panel_bridge_add(dev, panel);
-		if (IS_ERR(dsi->next_bridge)) {
-			ret = PTR_ERR(dsi->next_bridge);
-			goto err_unregister_host;
-		}
-	}
-
 	dsi->driver_data = of_device_get_match_data(dev);
 
 	dsi->engine_clk = devm_clk_get(dev, "engine");
@@ -1098,14 +1109,6 @@ static int mtk_dsi_probe(struct platform_device *pdev)
 	dsi->bridge.of_node = dev->of_node;
 	dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
 
-	drm_bridge_add(&dsi->bridge);
-
-	ret = component_add(&pdev->dev, &mtk_dsi_component_ops);
-	if (ret) {
-		dev_err(&pdev->dev, "failed to add component: %d\n", ret);
-		goto err_unregister_host;
-	}
-
 	return 0;
 
 err_unregister_host:
@@ -1118,8 +1121,6 @@ static int mtk_dsi_remove(struct platform_device *pdev)
 	struct mtk_dsi *dsi = platform_get_drvdata(pdev);
 
 	mtk_output_dsi_disable(dsi);
-	drm_bridge_remove(&dsi->bridge);
-	component_del(&pdev->dev, &mtk_dsi_component_ops);
 	mipi_dsi_host_unregister(&dsi->host);
 
 	return 0;
-- 
2.33.1

[PATCH v4] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[AngeloGioacchino Del Regno]

DRM bridge drivers are now attaching their DSI device at probe time,
which requires us to register our DSI host in order to let the bridge
to probe: this recently started producing an endless -EPROBE_DEFER
loop on some machines that are using external bridges, like the
parade-ps8640, found on the ACER Chromebook R13.

Now that the DSI hosts/devices probe sequence is documented, we can
do adjustments to the mtk_dsi driver as to both fix now and make sure
to avoid this situation in the future: for this, following what is
documented in drm_bridge.c, move the mtk_dsi component_add() to the
mtk_dsi_ops.attach callback and delete it in the detach callback;
keeping in mind that we are registering a drm_bridge for our DSI,
which is only used/attached if the DSI Host is bound, it wouldn't
make sense to keep adding our bridge at probe time (as it would
be useless to have it if mtk_dsi_ops.attach() fails!), so also move
that one to the dsi host attach function (and remove it in detach).

Cc: <stable@vger.kernel.org> # 5.15.x
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>

---
 drivers/gpu/drm/mediatek/mtk_dsi.c | 167 +++++++++++++++--------------
 1 file changed, 84 insertions(+), 83 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index 5d90d2eb0019..bced4c7d668e 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -786,18 +786,101 @@ void mtk_dsi_ddp_stop(struct device *dev)
 	mtk_dsi_poweroff(dsi);
 }
 
+static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi)
+{
+	int ret;
+
+	ret = drm_simple_encoder_init(drm, &dsi->encoder,
+				      DRM_MODE_ENCODER_DSI);
+	if (ret) {
+		DRM_ERROR("Failed to encoder init to drm\n");
+		return ret;
+	}
+
+	dsi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
+
+	ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL,
+				DRM_BRIDGE_ATTACH_NO_CONNECTOR);
+	if (ret)
+		goto err_cleanup_encoder;
+
+	dsi->connector = drm_bridge_connector_init(drm, &dsi->encoder);
+	if (IS_ERR(dsi->connector)) {
+		DRM_ERROR("Unable to create bridge connector\n");
+		ret = PTR_ERR(dsi->connector);
+		goto err_cleanup_encoder;
+	}
+	drm_connector_attach_encoder(dsi->connector, &dsi->encoder);
+
+	return 0;
+
+err_cleanup_encoder:
+	drm_encoder_cleanup(&dsi->encoder);
+	return ret;
+}
+
+static int mtk_dsi_bind(struct device *dev, struct device *master, void *data)
+{
+	int ret;
+	struct drm_device *drm = data;
+	struct mtk_dsi *dsi = dev_get_drvdata(dev);
+
+	ret = mtk_dsi_encoder_init(drm, dsi);
+	if (ret)
+		return ret;
+
+	return device_reset_optional(dev);
+}
+
+static void mtk_dsi_unbind(struct device *dev, struct device *master,
+			   void *data)
+{
+	struct mtk_dsi *dsi = dev_get_drvdata(dev);
+
+	drm_encoder_cleanup(&dsi->encoder);
+}
+
+static const struct component_ops mtk_dsi_component_ops = {
+	.bind = mtk_dsi_bind,
+	.unbind = mtk_dsi_unbind,
+};
+
 static int mtk_dsi_host_attach(struct mipi_dsi_host *host,
 			       struct mipi_dsi_device *device)
 {
 	struct mtk_dsi *dsi = host_to_dsi(host);
+	struct device *dev = host->dev;
+	int ret;
 
 	dsi->lanes = device->lanes;
 	dsi->format = device->format;
 	dsi->mode_flags = device->mode_flags;
+	dsi->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0);
+	if (IS_ERR(dsi->next_bridge))
+		return PTR_ERR(dsi->next_bridge);
+
+	drm_bridge_add(&dsi->bridge);
+
+	ret = component_add(host->dev, &mtk_dsi_component_ops);
+	if (ret) {
+		DRM_ERROR("failed to add dsi_host component: %d\n", ret);
+		drm_bridge_remove(&dsi->bridge);
+		return ret;
+	}
 
 	return 0;
 }
 
+static int mtk_dsi_host_detach(struct mipi_dsi_host *host,
+			       struct mipi_dsi_device *device)
+{
+	struct mtk_dsi *dsi = host_to_dsi(host);
+
+	component_del(host->dev, &mtk_dsi_component_ops);
+	drm_bridge_remove(&dsi->bridge);
+	return 0;
+}
+
 static void mtk_dsi_wait_for_idle(struct mtk_dsi *dsi)
 {
 	int ret;
@@ -938,73 +1021,14 @@ static ssize_t mtk_dsi_host_transfer(struct mipi_dsi_host *host,
 
 static const struct mipi_dsi_host_ops mtk_dsi_ops = {
 	.attach = mtk_dsi_host_attach,
+	.detach = mtk_dsi_host_detach,
 	.transfer = mtk_dsi_host_transfer,
 };
 
-static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi)
-{
-	int ret;
-
-	ret = drm_simple_encoder_init(drm, &dsi->encoder,
-				      DRM_MODE_ENCODER_DSI);
-	if (ret) {
-		DRM_ERROR("Failed to encoder init to drm\n");
-		return ret;
-	}
-
-	dsi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
-
-	ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL,
-				DRM_BRIDGE_ATTACH_NO_CONNECTOR);
-	if (ret)
-		goto err_cleanup_encoder;
-
-	dsi->connector = drm_bridge_connector_init(drm, &dsi->encoder);
-	if (IS_ERR(dsi->connector)) {
-		DRM_ERROR("Unable to create bridge connector\n");
-		ret = PTR_ERR(dsi->connector);
-		goto err_cleanup_encoder;
-	}
-	drm_connector_attach_encoder(dsi->connector, &dsi->encoder);
-
-	return 0;
-
-err_cleanup_encoder:
-	drm_encoder_cleanup(&dsi->encoder);
-	return ret;
-}
-
-static int mtk_dsi_bind(struct device *dev, struct device *master, void *data)
-{
-	int ret;
-	struct drm_device *drm = data;
-	struct mtk_dsi *dsi = dev_get_drvdata(dev);
-
-	ret = mtk_dsi_encoder_init(drm, dsi);
-	if (ret)
-		return ret;
-
-	return device_reset_optional(dev);
-}
-
-static void mtk_dsi_unbind(struct device *dev, struct device *master,
-			   void *data)
-{
-	struct mtk_dsi *dsi = dev_get_drvdata(dev);
-
-	drm_encoder_cleanup(&dsi->encoder);
-}
-
-static const struct component_ops mtk_dsi_component_ops = {
-	.bind = mtk_dsi_bind,
-	.unbind = mtk_dsi_unbind,
-};
-
 static int mtk_dsi_probe(struct platform_device *pdev)
 {
 	struct mtk_dsi *dsi;
 	struct device *dev = &pdev->dev;
-	struct drm_panel *panel;
 	struct resource *regs;
 	int irq_num;
 	int ret;
@@ -1021,19 +1045,6 @@ static int mtk_dsi_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0,
-					  &panel, &dsi->next_bridge);
-	if (ret)
-		goto err_unregister_host;
-
-	if (panel) {
-		dsi->next_bridge = devm_drm_panel_bridge_add(dev, panel);
-		if (IS_ERR(dsi->next_bridge)) {
-			ret = PTR_ERR(dsi->next_bridge);
-			goto err_unregister_host;
-		}
-	}
-
 	dsi->driver_data = of_device_get_match_data(dev);
 
 	dsi->engine_clk = devm_clk_get(dev, "engine");
@@ -1098,14 +1109,6 @@ static int mtk_dsi_probe(struct platform_device *pdev)
 	dsi->bridge.of_node = dev->of_node;
 	dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
 
-	drm_bridge_add(&dsi->bridge);
-
-	ret = component_add(&pdev->dev, &mtk_dsi_component_ops);
-	if (ret) {
-		dev_err(&pdev->dev, "failed to add component: %d\n", ret);
-		goto err_unregister_host;
-	}
-
 	return 0;
 
 err_unregister_host:
@@ -1118,8 +1121,6 @@ static int mtk_dsi_remove(struct platform_device *pdev)
 	struct mtk_dsi *dsi = platform_get_drvdata(pdev);
 
 	mtk_output_dsi_disable(dsi);
-	drm_bridge_remove(&dsi->bridge);
-	component_del(&pdev->dev, &mtk_dsi_component_ops);
 	mipi_dsi_host_unregister(&dsi->host);
 
 	return 0;
-- 
2.33.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH v4] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[CK Hu]

Hi, Angelo:

On Mon, 2022-01-31 at 09:55 +0100, AngeloGioacchino Del Regno wrote:
> DRM bridge drivers are now attaching their DSI device at probe time,
> which requires us to register our DSI host in order to let the bridge
> to probe: this recently started producing an endless -EPROBE_DEFER
> loop on some machines that are using external bridges, like the
> parade-ps8640, found on the ACER Chromebook R13.
> 
> Now that the DSI hosts/devices probe sequence is documented, we can
> do adjustments to the mtk_dsi driver as to both fix now and make sure
> to avoid this situation in the future: for this, following what is
> documented in drm_bridge.c, move the mtk_dsi component_add() to the
> mtk_dsi_ops.attach callback and delete it in the detach callback;
> keeping in mind that we are registering a drm_bridge for our DSI,
> which is only used/attached if the DSI Host is bound, it wouldn't
> make sense to keep adding our bridge at probe time (as it would
> be useless to have it if mtk_dsi_ops.attach() fails!), so also move
> that one to the dsi host attach function (and remove it in detach).
> 
> Cc: <stable@vger.kernel.org> # 5.15.x
> Signed-off-by: AngeloGioacchino Del Regno <
> angelogioacchino.delregno@collabora.com>
> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
> Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
> 
> ---
>  drivers/gpu/drm/mediatek/mtk_dsi.c | 167 +++++++++++++++----------
> ----
>  1 file changed, 84 insertions(+), 83 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c
> b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index 5d90d2eb0019..bced4c7d668e 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -786,18 +786,101 @@ void mtk_dsi_ddp_stop(struct device *dev)
>  	mtk_dsi_poweroff(dsi);
>  }
>  
> 

[snip]

> +
>  static int mtk_dsi_host_attach(struct mipi_dsi_host *host,
>  			       struct mipi_dsi_device *device)
>  {
>  	struct mtk_dsi *dsi = host_to_dsi(host);
> +	struct device *dev = host->dev;
> +	int ret;
>  
>  	dsi->lanes = device->lanes;
>  	dsi->format = device->format;
>  	dsi->mode_flags = device->mode_flags;
> +	dsi->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0,
> 0);

The original would process panel. Why do you remove the panel part?
It's better that someone has a platform of DSI->Panel to test this
patch.

Regards,
CK

> +	if (IS_ERR(dsi->next_bridge))
> +		return PTR_ERR(dsi->next_bridge);
> +
> +	drm_bridge_add(&dsi->bridge);
> +
> +	ret = component_add(host->dev, &mtk_dsi_component_ops);
> +	if (ret) {
> +		DRM_ERROR("failed to add dsi_host component: %d\n",
> ret);
> +		drm_bridge_remove(&dsi->bridge);
> +		return ret;
> +	}
>  
>  	return 0;
>  }
>  
> +static int mtk_dsi_host_detach(struct mipi_dsi_host *host,
> +			       struct mipi_dsi_device *device)
> +{
> +	struct mtk_dsi *dsi = host_to_dsi(host);
> +
> +	component_del(host->dev, &mtk_dsi_component_ops);
> +	drm_bridge_remove(&dsi->bridge);
> +	return 0;
> +}
> +
>  static void mtk_dsi_wait_for_idle(struct mtk_dsi *dsi)
>  {
>  	int ret;
> @@ -938,73 +1021,14 @@ static ssize_t mtk_dsi_host_transfer(struct
> mipi_dsi_host *host,
>  
>  static const struct mipi_dsi_host_ops mtk_dsi_ops = {
>  	.attach = mtk_dsi_host_attach,
> +	.detach = mtk_dsi_host_detach,
>  	.transfer = mtk_dsi_host_transfer,
>  };
>  
> 

[snip]

> -
>  static int mtk_dsi_probe(struct platform_device *pdev)
>  {
>  	struct mtk_dsi *dsi;
>  	struct device *dev = &pdev->dev;
> -	struct drm_panel *panel;
>  	struct resource *regs;
>  	int irq_num;
>  	int ret;
> @@ -1021,19 +1045,6 @@ static int mtk_dsi_probe(struct
> platform_device *pdev)
>  		return ret;
>  	}
>  
> -	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0,
> -					  &panel, &dsi->next_bridge);
> -	if (ret)
> -		goto err_unregister_host;
> -
> -	if (panel) {
> -		dsi->next_bridge = devm_drm_panel_bridge_add(dev,
> panel);
> -		if (IS_ERR(dsi->next_bridge)) {
> -			ret = PTR_ERR(dsi->next_bridge);
> -			goto err_unregister_host;
> -		}
> -	}
> -
>  	dsi->driver_data = of_device_get_match_data(dev);
>  
>  	dsi->engine_clk = devm_clk_get(dev, "engine");
> @@ -1098,14 +1109,6 @@ static int mtk_dsi_probe(struct
> platform_device *pdev)
>  	dsi->bridge.of_node = dev->of_node;
>  	dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
>  
> -	drm_bridge_add(&dsi->bridge);
> -
> -	ret = component_add(&pdev->dev, &mtk_dsi_component_ops);
> -	if (ret) {
> -		dev_err(&pdev->dev, "failed to add component: %d\n",
> ret);
> -		goto err_unregister_host;
> -	}
> -
>  	return 0;
>  
>  err_unregister_host:
> @@ -1118,8 +1121,6 @@ static int mtk_dsi_remove(struct
> platform_device *pdev)
>  	struct mtk_dsi *dsi = platform_get_drvdata(pdev);
>  
>  	mtk_output_dsi_disable(dsi);
> -	drm_bridge_remove(&dsi->bridge);
> -	component_del(&pdev->dev, &mtk_dsi_component_ops);
>  	mipi_dsi_host_unregister(&dsi->host);
>  
>  	return 0;

Re: [PATCH v4] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[CK Hu]

Hi, Angelo:

On Mon, 2022-01-31 at 09:55 +0100, AngeloGioacchino Del Regno wrote:
> DRM bridge drivers are now attaching their DSI device at probe time,
> which requires us to register our DSI host in order to let the bridge
> to probe: this recently started producing an endless -EPROBE_DEFER
> loop on some machines that are using external bridges, like the
> parade-ps8640, found on the ACER Chromebook R13.
> 
> Now that the DSI hosts/devices probe sequence is documented, we can
> do adjustments to the mtk_dsi driver as to both fix now and make sure
> to avoid this situation in the future: for this, following what is
> documented in drm_bridge.c, move the mtk_dsi component_add() to the
> mtk_dsi_ops.attach callback and delete it in the detach callback;
> keeping in mind that we are registering a drm_bridge for our DSI,
> which is only used/attached if the DSI Host is bound, it wouldn't
> make sense to keep adding our bridge at probe time (as it would
> be useless to have it if mtk_dsi_ops.attach() fails!), so also move
> that one to the dsi host attach function (and remove it in detach).
> 
> Cc: <stable@vger.kernel.org> # 5.15.x
> Signed-off-by: AngeloGioacchino Del Regno <
> angelogioacchino.delregno@collabora.com>
> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
> Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
> 
> ---
>  drivers/gpu/drm/mediatek/mtk_dsi.c | 167 +++++++++++++++----------
> ----
>  1 file changed, 84 insertions(+), 83 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c
> b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index 5d90d2eb0019..bced4c7d668e 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -786,18 +786,101 @@ void mtk_dsi_ddp_stop(struct device *dev)
>  	mtk_dsi_poweroff(dsi);
>  }
>  
> 

[snip]

> +
>  static int mtk_dsi_host_attach(struct mipi_dsi_host *host,
>  			       struct mipi_dsi_device *device)
>  {
>  	struct mtk_dsi *dsi = host_to_dsi(host);
> +	struct device *dev = host->dev;
> +	int ret;
>  
>  	dsi->lanes = device->lanes;
>  	dsi->format = device->format;
>  	dsi->mode_flags = device->mode_flags;
> +	dsi->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0,
> 0);

The original would process panel. Why do you remove the panel part?
It's better that someone has a platform of DSI->Panel to test this
patch.

Regards,
CK

> +	if (IS_ERR(dsi->next_bridge))
> +		return PTR_ERR(dsi->next_bridge);
> +
> +	drm_bridge_add(&dsi->bridge);
> +
> +	ret = component_add(host->dev, &mtk_dsi_component_ops);
> +	if (ret) {
> +		DRM_ERROR("failed to add dsi_host component: %d\n",
> ret);
> +		drm_bridge_remove(&dsi->bridge);
> +		return ret;
> +	}
>  
>  	return 0;
>  }
>  
> +static int mtk_dsi_host_detach(struct mipi_dsi_host *host,
> +			       struct mipi_dsi_device *device)
> +{
> +	struct mtk_dsi *dsi = host_to_dsi(host);
> +
> +	component_del(host->dev, &mtk_dsi_component_ops);
> +	drm_bridge_remove(&dsi->bridge);
> +	return 0;
> +}
> +
>  static void mtk_dsi_wait_for_idle(struct mtk_dsi *dsi)
>  {
>  	int ret;
> @@ -938,73 +1021,14 @@ static ssize_t mtk_dsi_host_transfer(struct
> mipi_dsi_host *host,
>  
>  static const struct mipi_dsi_host_ops mtk_dsi_ops = {
>  	.attach = mtk_dsi_host_attach,
> +	.detach = mtk_dsi_host_detach,
>  	.transfer = mtk_dsi_host_transfer,
>  };
>  
> 

[snip]

> -
>  static int mtk_dsi_probe(struct platform_device *pdev)
>  {
>  	struct mtk_dsi *dsi;
>  	struct device *dev = &pdev->dev;
> -	struct drm_panel *panel;
>  	struct resource *regs;
>  	int irq_num;
>  	int ret;
> @@ -1021,19 +1045,6 @@ static int mtk_dsi_probe(struct
> platform_device *pdev)
>  		return ret;
>  	}
>  
> -	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0,
> -					  &panel, &dsi->next_bridge);
> -	if (ret)
> -		goto err_unregister_host;
> -
> -	if (panel) {
> -		dsi->next_bridge = devm_drm_panel_bridge_add(dev,
> panel);
> -		if (IS_ERR(dsi->next_bridge)) {
> -			ret = PTR_ERR(dsi->next_bridge);
> -			goto err_unregister_host;
> -		}
> -	}
> -
>  	dsi->driver_data = of_device_get_match_data(dev);
>  
>  	dsi->engine_clk = devm_clk_get(dev, "engine");
> @@ -1098,14 +1109,6 @@ static int mtk_dsi_probe(struct
> platform_device *pdev)
>  	dsi->bridge.of_node = dev->of_node;
>  	dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
>  
> -	drm_bridge_add(&dsi->bridge);
> -
> -	ret = component_add(&pdev->dev, &mtk_dsi_component_ops);
> -	if (ret) {
> -		dev_err(&pdev->dev, "failed to add component: %d\n",
> ret);
> -		goto err_unregister_host;
> -	}
> -
>  	return 0;
>  
>  err_unregister_host:
> @@ -1118,8 +1121,6 @@ static int mtk_dsi_remove(struct
> platform_device *pdev)
>  	struct mtk_dsi *dsi = platform_get_drvdata(pdev);
>  
>  	mtk_output_dsi_disable(dsi);
> -	drm_bridge_remove(&dsi->bridge);
> -	component_del(&pdev->dev, &mtk_dsi_component_ops);
>  	mipi_dsi_host_unregister(&dsi->host);
>  
>  	return 0;

Re: [PATCH v4] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[CK Hu]

Hi, Angelo:

On Mon, 2022-01-31 at 09:55 +0100, AngeloGioacchino Del Regno wrote:
> DRM bridge drivers are now attaching their DSI device at probe time,
> which requires us to register our DSI host in order to let the bridge
> to probe: this recently started producing an endless -EPROBE_DEFER
> loop on some machines that are using external bridges, like the
> parade-ps8640, found on the ACER Chromebook R13.
> 
> Now that the DSI hosts/devices probe sequence is documented, we can
> do adjustments to the mtk_dsi driver as to both fix now and make sure
> to avoid this situation in the future: for this, following what is
> documented in drm_bridge.c, move the mtk_dsi component_add() to the
> mtk_dsi_ops.attach callback and delete it in the detach callback;
> keeping in mind that we are registering a drm_bridge for our DSI,
> which is only used/attached if the DSI Host is bound, it wouldn't
> make sense to keep adding our bridge at probe time (as it would
> be useless to have it if mtk_dsi_ops.attach() fails!), so also move
> that one to the dsi host attach function (and remove it in detach).
> 
> Cc: <stable@vger.kernel.org> # 5.15.x
> Signed-off-by: AngeloGioacchino Del Regno <
> angelogioacchino.delregno@collabora.com>
> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
> Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
> 
> ---
>  drivers/gpu/drm/mediatek/mtk_dsi.c | 167 +++++++++++++++----------
> ----
>  1 file changed, 84 insertions(+), 83 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c
> b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index 5d90d2eb0019..bced4c7d668e 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -786,18 +786,101 @@ void mtk_dsi_ddp_stop(struct device *dev)
>  	mtk_dsi_poweroff(dsi);
>  }
>  
> 

[snip]

> +
>  static int mtk_dsi_host_attach(struct mipi_dsi_host *host,
>  			       struct mipi_dsi_device *device)
>  {
>  	struct mtk_dsi *dsi = host_to_dsi(host);
> +	struct device *dev = host->dev;
> +	int ret;
>  
>  	dsi->lanes = device->lanes;
>  	dsi->format = device->format;
>  	dsi->mode_flags = device->mode_flags;
> +	dsi->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0,
> 0);

The original would process panel. Why do you remove the panel part?
It's better that someone has a platform of DSI->Panel to test this
patch.

Regards,
CK

> +	if (IS_ERR(dsi->next_bridge))
> +		return PTR_ERR(dsi->next_bridge);
> +
> +	drm_bridge_add(&dsi->bridge);
> +
> +	ret = component_add(host->dev, &mtk_dsi_component_ops);
> +	if (ret) {
> +		DRM_ERROR("failed to add dsi_host component: %d\n",
> ret);
> +		drm_bridge_remove(&dsi->bridge);
> +		return ret;
> +	}
>  
>  	return 0;
>  }
>  
> +static int mtk_dsi_host_detach(struct mipi_dsi_host *host,
> +			       struct mipi_dsi_device *device)
> +{
> +	struct mtk_dsi *dsi = host_to_dsi(host);
> +
> +	component_del(host->dev, &mtk_dsi_component_ops);
> +	drm_bridge_remove(&dsi->bridge);
> +	return 0;
> +}
> +
>  static void mtk_dsi_wait_for_idle(struct mtk_dsi *dsi)
>  {
>  	int ret;
> @@ -938,73 +1021,14 @@ static ssize_t mtk_dsi_host_transfer(struct
> mipi_dsi_host *host,
>  
>  static const struct mipi_dsi_host_ops mtk_dsi_ops = {
>  	.attach = mtk_dsi_host_attach,
> +	.detach = mtk_dsi_host_detach,
>  	.transfer = mtk_dsi_host_transfer,
>  };
>  
> 

[snip]

> -
>  static int mtk_dsi_probe(struct platform_device *pdev)
>  {
>  	struct mtk_dsi *dsi;
>  	struct device *dev = &pdev->dev;
> -	struct drm_panel *panel;
>  	struct resource *regs;
>  	int irq_num;
>  	int ret;
> @@ -1021,19 +1045,6 @@ static int mtk_dsi_probe(struct
> platform_device *pdev)
>  		return ret;
>  	}
>  
> -	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0,
> -					  &panel, &dsi->next_bridge);
> -	if (ret)
> -		goto err_unregister_host;
> -
> -	if (panel) {
> -		dsi->next_bridge = devm_drm_panel_bridge_add(dev,
> panel);
> -		if (IS_ERR(dsi->next_bridge)) {
> -			ret = PTR_ERR(dsi->next_bridge);
> -			goto err_unregister_host;
> -		}
> -	}
> -
>  	dsi->driver_data = of_device_get_match_data(dev);
>  
>  	dsi->engine_clk = devm_clk_get(dev, "engine");
> @@ -1098,14 +1109,6 @@ static int mtk_dsi_probe(struct
> platform_device *pdev)
>  	dsi->bridge.of_node = dev->of_node;
>  	dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
>  
> -	drm_bridge_add(&dsi->bridge);
> -
> -	ret = component_add(&pdev->dev, &mtk_dsi_component_ops);
> -	if (ret) {
> -		dev_err(&pdev->dev, "failed to add component: %d\n",
> ret);
> -		goto err_unregister_host;
> -	}
> -
>  	return 0;
>  
>  err_unregister_host:
> @@ -1118,8 +1121,6 @@ static int mtk_dsi_remove(struct
> platform_device *pdev)
>  	struct mtk_dsi *dsi = platform_get_drvdata(pdev);
>  
>  	mtk_output_dsi_disable(dsi);
> -	drm_bridge_remove(&dsi->bridge);
> -	component_del(&pdev->dev, &mtk_dsi_component_ops);
>  	mipi_dsi_host_unregister(&dsi->host);
>  
>  	return 0;


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Re: [PATCH v4] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[CK Hu]

Hi, Angelo:

On Mon, 2022-01-31 at 09:55 +0100, AngeloGioacchino Del Regno wrote:
> DRM bridge drivers are now attaching their DSI device at probe time,
> which requires us to register our DSI host in order to let the bridge
> to probe: this recently started producing an endless -EPROBE_DEFER
> loop on some machines that are using external bridges, like the
> parade-ps8640, found on the ACER Chromebook R13.
> 
> Now that the DSI hosts/devices probe sequence is documented, we can
> do adjustments to the mtk_dsi driver as to both fix now and make sure
> to avoid this situation in the future: for this, following what is
> documented in drm_bridge.c, move the mtk_dsi component_add() to the
> mtk_dsi_ops.attach callback and delete it in the detach callback;
> keeping in mind that we are registering a drm_bridge for our DSI,
> which is only used/attached if the DSI Host is bound, it wouldn't
> make sense to keep adding our bridge at probe time (as it would
> be useless to have it if mtk_dsi_ops.attach() fails!), so also move
> that one to the dsi host attach function (and remove it in detach).
> 
> Cc: <stable@vger.kernel.org> # 5.15.x
> Signed-off-by: AngeloGioacchino Del Regno <
> angelogioacchino.delregno@collabora.com>
> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
> Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
> 
> ---
>  drivers/gpu/drm/mediatek/mtk_dsi.c | 167 +++++++++++++++----------
> ----
>  1 file changed, 84 insertions(+), 83 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c
> b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index 5d90d2eb0019..bced4c7d668e 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -786,18 +786,101 @@ void mtk_dsi_ddp_stop(struct device *dev)
>  	mtk_dsi_poweroff(dsi);
>  }
>  
> 

[snip]

> +
>  static int mtk_dsi_host_attach(struct mipi_dsi_host *host,
>  			       struct mipi_dsi_device *device)
>  {
>  	struct mtk_dsi *dsi = host_to_dsi(host);
> +	struct device *dev = host->dev;
> +	int ret;
>  
>  	dsi->lanes = device->lanes;
>  	dsi->format = device->format;
>  	dsi->mode_flags = device->mode_flags;
> +	dsi->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0,
> 0);

The original would process panel. Why do you remove the panel part?
It's better that someone has a platform of DSI->Panel to test this
patch.

Regards,
CK

> +	if (IS_ERR(dsi->next_bridge))
> +		return PTR_ERR(dsi->next_bridge);
> +
> +	drm_bridge_add(&dsi->bridge);
> +
> +	ret = component_add(host->dev, &mtk_dsi_component_ops);
> +	if (ret) {
> +		DRM_ERROR("failed to add dsi_host component: %d\n",
> ret);
> +		drm_bridge_remove(&dsi->bridge);
> +		return ret;
> +	}
>  
>  	return 0;
>  }
>  
> +static int mtk_dsi_host_detach(struct mipi_dsi_host *host,
> +			       struct mipi_dsi_device *device)
> +{
> +	struct mtk_dsi *dsi = host_to_dsi(host);
> +
> +	component_del(host->dev, &mtk_dsi_component_ops);
> +	drm_bridge_remove(&dsi->bridge);
> +	return 0;
> +}
> +
>  static void mtk_dsi_wait_for_idle(struct mtk_dsi *dsi)
>  {
>  	int ret;
> @@ -938,73 +1021,14 @@ static ssize_t mtk_dsi_host_transfer(struct
> mipi_dsi_host *host,
>  
>  static const struct mipi_dsi_host_ops mtk_dsi_ops = {
>  	.attach = mtk_dsi_host_attach,
> +	.detach = mtk_dsi_host_detach,
>  	.transfer = mtk_dsi_host_transfer,
>  };
>  
> 

[snip]

> -
>  static int mtk_dsi_probe(struct platform_device *pdev)
>  {
>  	struct mtk_dsi *dsi;
>  	struct device *dev = &pdev->dev;
> -	struct drm_panel *panel;
>  	struct resource *regs;
>  	int irq_num;
>  	int ret;
> @@ -1021,19 +1045,6 @@ static int mtk_dsi_probe(struct
> platform_device *pdev)
>  		return ret;
>  	}
>  
> -	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0,
> -					  &panel, &dsi->next_bridge);
> -	if (ret)
> -		goto err_unregister_host;
> -
> -	if (panel) {
> -		dsi->next_bridge = devm_drm_panel_bridge_add(dev,
> panel);
> -		if (IS_ERR(dsi->next_bridge)) {
> -			ret = PTR_ERR(dsi->next_bridge);
> -			goto err_unregister_host;
> -		}
> -	}
> -
>  	dsi->driver_data = of_device_get_match_data(dev);
>  
>  	dsi->engine_clk = devm_clk_get(dev, "engine");
> @@ -1098,14 +1109,6 @@ static int mtk_dsi_probe(struct
> platform_device *pdev)
>  	dsi->bridge.of_node = dev->of_node;
>  	dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
>  
> -	drm_bridge_add(&dsi->bridge);
> -
> -	ret = component_add(&pdev->dev, &mtk_dsi_component_ops);
> -	if (ret) {
> -		dev_err(&pdev->dev, "failed to add component: %d\n",
> ret);
> -		goto err_unregister_host;
> -	}
> -
>  	return 0;
>  
>  err_unregister_host:
> @@ -1118,8 +1121,6 @@ static int mtk_dsi_remove(struct
> platform_device *pdev)
>  	struct mtk_dsi *dsi = platform_get_drvdata(pdev);
>  
>  	mtk_output_dsi_disable(dsi);
> -	drm_bridge_remove(&dsi->bridge);
> -	component_del(&pdev->dev, &mtk_dsi_component_ops);
>  	mipi_dsi_host_unregister(&dsi->host);
>  
>  	return 0;


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Re: [PATCH v4] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[CK Hu]

Hi, Angelo:

On Tue, 2022-02-08 at 16:20 +0800, CK Hu wrote:
> Hi, Angelo:
> 
> On Mon, 2022-01-31 at 09:55 +0100, AngeloGioacchino Del Regno wrote:
> > DRM bridge drivers are now attaching their DSI device at probe
> > time,
> > which requires us to register our DSI host in order to let the
> > bridge
> > to probe: this recently started producing an endless -EPROBE_DEFER
> > loop on some machines that are using external bridges, like the
> > parade-ps8640, found on the ACER Chromebook R13.
> > 
> > Now that the DSI hosts/devices probe sequence is documented, we can
> > do adjustments to the mtk_dsi driver as to both fix now and make
> > sure
> > to avoid this situation in the future: for this, following what is
> > documented in drm_bridge.c, move the mtk_dsi component_add() to the
> > mtk_dsi_ops.attach callback and delete it in the detach callback;
> > keeping in mind that we are registering a drm_bridge for our DSI,
> > which is only used/attached if the DSI Host is bound, it wouldn't
> > make sense to keep adding our bridge at probe time (as it would
> > be useless to have it if mtk_dsi_ops.attach() fails!), so also move
> > that one to the dsi host attach function (and remove it in detach).
> > 
> > Cc: <stable@vger.kernel.org> # 5.15.x
> > Signed-off-by: AngeloGioacchino Del Regno <
> > angelogioacchino.delregno@collabora.com>
> > Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
> > Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
> > 
> > ---
> >  drivers/gpu/drm/mediatek/mtk_dsi.c | 167 +++++++++++++++----------
> > ----
> >  1 file changed, 84 insertions(+), 83 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c
> > b/drivers/gpu/drm/mediatek/mtk_dsi.c
> > index 5d90d2eb0019..bced4c7d668e 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> > @@ -786,18 +786,101 @@ void mtk_dsi_ddp_stop(struct device *dev)
> >  	mtk_dsi_poweroff(dsi);
> >  }
> >  
> > 
> 
> [snip]
> 
> > +
> >  static int mtk_dsi_host_attach(struct mipi_dsi_host *host,
> >  			       struct mipi_dsi_device *device)
> >  {
> >  	struct mtk_dsi *dsi = host_to_dsi(host);
> > +	struct device *dev = host->dev;
> > +	int ret;
> >  
> >  	dsi->lanes = device->lanes;
> >  	dsi->format = device->format;
> >  	dsi->mode_flags = device->mode_flags;
> > +	dsi->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0,
> > 0);
> 
> The original would process panel. Why do you remove the panel part?
> It's better that someone has a platform of DSI->Panel to test this
> patch.

Sorry, devm_drm_of_get_bridge() has processed the panel part, so for
this patch,

Reviewed-by: CK Hu <ck.hu@mediatek.com>

> 
> Regards,
> CK
> 
> > +	if (IS_ERR(dsi->next_bridge))
> > +		return PTR_ERR(dsi->next_bridge);
> > +
> > +	drm_bridge_add(&dsi->bridge);
> > +
> > +	ret = component_add(host->dev, &mtk_dsi_component_ops);
> > +	if (ret) {
> > +		DRM_ERROR("failed to add dsi_host component: %d\n",
> > ret);
> > +		drm_bridge_remove(&dsi->bridge);
> > +		return ret;
> > +	}
> >  
> >  	return 0;
> >  }
> >  
> > +static int mtk_dsi_host_detach(struct mipi_dsi_host *host,
> > +			       struct mipi_dsi_device *device)
> > +{
> > +	struct mtk_dsi *dsi = host_to_dsi(host);
> > +
> > +	component_del(host->dev, &mtk_dsi_component_ops);
> > +	drm_bridge_remove(&dsi->bridge);
> > +	return 0;
> > +}
> > +
> >  static void mtk_dsi_wait_for_idle(struct mtk_dsi *dsi)
> >  {
> >  	int ret;
> > @@ -938,73 +1021,14 @@ static ssize_t mtk_dsi_host_transfer(struct
> > mipi_dsi_host *host,
> >  
> >  static const struct mipi_dsi_host_ops mtk_dsi_ops = {
> >  	.attach = mtk_dsi_host_attach,
> > +	.detach = mtk_dsi_host_detach,
> >  	.transfer = mtk_dsi_host_transfer,
> >  };
> >  
> > 
> 
> [snip]
> 
> > -
> >  static int mtk_dsi_probe(struct platform_device *pdev)
> >  {
> >  	struct mtk_dsi *dsi;
> >  	struct device *dev = &pdev->dev;
> > -	struct drm_panel *panel;
> >  	struct resource *regs;
> >  	int irq_num;
> >  	int ret;
> > @@ -1021,19 +1045,6 @@ static int mtk_dsi_probe(struct
> > platform_device *pdev)
> >  		return ret;
> >  	}
> >  
> > -	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0,
> > -					  &panel, &dsi->next_bridge);
> > -	if (ret)
> > -		goto err_unregister_host;
> > -
> > -	if (panel) {
> > -		dsi->next_bridge = devm_drm_panel_bridge_add(dev,
> > panel);
> > -		if (IS_ERR(dsi->next_bridge)) {
> > -			ret = PTR_ERR(dsi->next_bridge);
> > -			goto err_unregister_host;
> > -		}
> > -	}
> > -
> >  	dsi->driver_data = of_device_get_match_data(dev);
> >  
> >  	dsi->engine_clk = devm_clk_get(dev, "engine");
> > @@ -1098,14 +1109,6 @@ static int mtk_dsi_probe(struct
> > platform_device *pdev)
> >  	dsi->bridge.of_node = dev->of_node;
> >  	dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
> >  
> > -	drm_bridge_add(&dsi->bridge);
> > -
> > -	ret = component_add(&pdev->dev, &mtk_dsi_component_ops);
> > -	if (ret) {
> > -		dev_err(&pdev->dev, "failed to add component: %d\n",
> > ret);
> > -		goto err_unregister_host;
> > -	}
> > -
> >  	return 0;
> >  
> >  err_unregister_host:
> > @@ -1118,8 +1121,6 @@ static int mtk_dsi_remove(struct
> > platform_device *pdev)
> >  	struct mtk_dsi *dsi = platform_get_drvdata(pdev);
> >  
> >  	mtk_output_dsi_disable(dsi);
> > -	drm_bridge_remove(&dsi->bridge);
> > -	component_del(&pdev->dev, &mtk_dsi_component_ops);
> >  	mipi_dsi_host_unregister(&dsi->host);
> >  
> >  	return 0;

Re: [PATCH v4] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[CK Hu]

Hi, Angelo:

On Tue, 2022-02-08 at 16:20 +0800, CK Hu wrote:
> Hi, Angelo:
> 
> On Mon, 2022-01-31 at 09:55 +0100, AngeloGioacchino Del Regno wrote:
> > DRM bridge drivers are now attaching their DSI device at probe
> > time,
> > which requires us to register our DSI host in order to let the
> > bridge
> > to probe: this recently started producing an endless -EPROBE_DEFER
> > loop on some machines that are using external bridges, like the
> > parade-ps8640, found on the ACER Chromebook R13.
> > 
> > Now that the DSI hosts/devices probe sequence is documented, we can
> > do adjustments to the mtk_dsi driver as to both fix now and make
> > sure
> > to avoid this situation in the future: for this, following what is
> > documented in drm_bridge.c, move the mtk_dsi component_add() to the
> > mtk_dsi_ops.attach callback and delete it in the detach callback;
> > keeping in mind that we are registering a drm_bridge for our DSI,
> > which is only used/attached if the DSI Host is bound, it wouldn't
> > make sense to keep adding our bridge at probe time (as it would
> > be useless to have it if mtk_dsi_ops.attach() fails!), so also move
> > that one to the dsi host attach function (and remove it in detach).
> > 
> > Cc: <stable@vger.kernel.org> # 5.15.x
> > Signed-off-by: AngeloGioacchino Del Regno <
> > angelogioacchino.delregno@collabora.com>
> > Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
> > Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
> > 
> > ---
> >  drivers/gpu/drm/mediatek/mtk_dsi.c | 167 +++++++++++++++----------
> > ----
> >  1 file changed, 84 insertions(+), 83 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c
> > b/drivers/gpu/drm/mediatek/mtk_dsi.c
> > index 5d90d2eb0019..bced4c7d668e 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> > @@ -786,18 +786,101 @@ void mtk_dsi_ddp_stop(struct device *dev)
> >  	mtk_dsi_poweroff(dsi);
> >  }
> >  
> > 
> 
> [snip]
> 
> > +
> >  static int mtk_dsi_host_attach(struct mipi_dsi_host *host,
> >  			       struct mipi_dsi_device *device)
> >  {
> >  	struct mtk_dsi *dsi = host_to_dsi(host);
> > +	struct device *dev = host->dev;
> > +	int ret;
> >  
> >  	dsi->lanes = device->lanes;
> >  	dsi->format = device->format;
> >  	dsi->mode_flags = device->mode_flags;
> > +	dsi->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0,
> > 0);
> 
> The original would process panel. Why do you remove the panel part?
> It's better that someone has a platform of DSI->Panel to test this
> patch.

Sorry, devm_drm_of_get_bridge() has processed the panel part, so for
this patch,

Reviewed-by: CK Hu <ck.hu@mediatek.com>

> 
> Regards,
> CK
> 
> > +	if (IS_ERR(dsi->next_bridge))
> > +		return PTR_ERR(dsi->next_bridge);
> > +
> > +	drm_bridge_add(&dsi->bridge);
> > +
> > +	ret = component_add(host->dev, &mtk_dsi_component_ops);
> > +	if (ret) {
> > +		DRM_ERROR("failed to add dsi_host component: %d\n",
> > ret);
> > +		drm_bridge_remove(&dsi->bridge);
> > +		return ret;
> > +	}
> >  
> >  	return 0;
> >  }
> >  
> > +static int mtk_dsi_host_detach(struct mipi_dsi_host *host,
> > +			       struct mipi_dsi_device *device)
> > +{
> > +	struct mtk_dsi *dsi = host_to_dsi(host);
> > +
> > +	component_del(host->dev, &mtk_dsi_component_ops);
> > +	drm_bridge_remove(&dsi->bridge);
> > +	return 0;
> > +}
> > +
> >  static void mtk_dsi_wait_for_idle(struct mtk_dsi *dsi)
> >  {
> >  	int ret;
> > @@ -938,73 +1021,14 @@ static ssize_t mtk_dsi_host_transfer(struct
> > mipi_dsi_host *host,
> >  
> >  static const struct mipi_dsi_host_ops mtk_dsi_ops = {
> >  	.attach = mtk_dsi_host_attach,
> > +	.detach = mtk_dsi_host_detach,
> >  	.transfer = mtk_dsi_host_transfer,
> >  };
> >  
> > 
> 
> [snip]
> 
> > -
> >  static int mtk_dsi_probe(struct platform_device *pdev)
> >  {
> >  	struct mtk_dsi *dsi;
> >  	struct device *dev = &pdev->dev;
> > -	struct drm_panel *panel;
> >  	struct resource *regs;
> >  	int irq_num;
> >  	int ret;
> > @@ -1021,19 +1045,6 @@ static int mtk_dsi_probe(struct
> > platform_device *pdev)
> >  		return ret;
> >  	}
> >  
> > -	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0,
> > -					  &panel, &dsi->next_bridge);
> > -	if (ret)
> > -		goto err_unregister_host;
> > -
> > -	if (panel) {
> > -		dsi->next_bridge = devm_drm_panel_bridge_add(dev,
> > panel);
> > -		if (IS_ERR(dsi->next_bridge)) {
> > -			ret = PTR_ERR(dsi->next_bridge);
> > -			goto err_unregister_host;
> > -		}
> > -	}
> > -
> >  	dsi->driver_data = of_device_get_match_data(dev);
> >  
> >  	dsi->engine_clk = devm_clk_get(dev, "engine");
> > @@ -1098,14 +1109,6 @@ static int mtk_dsi_probe(struct
> > platform_device *pdev)
> >  	dsi->bridge.of_node = dev->of_node;
> >  	dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
> >  
> > -	drm_bridge_add(&dsi->bridge);
> > -
> > -	ret = component_add(&pdev->dev, &mtk_dsi_component_ops);
> > -	if (ret) {
> > -		dev_err(&pdev->dev, "failed to add component: %d\n",
> > ret);
> > -		goto err_unregister_host;
> > -	}
> > -
> >  	return 0;
> >  
> >  err_unregister_host:
> > @@ -1118,8 +1121,6 @@ static int mtk_dsi_remove(struct
> > platform_device *pdev)
> >  	struct mtk_dsi *dsi = platform_get_drvdata(pdev);
> >  
> >  	mtk_output_dsi_disable(dsi);
> > -	drm_bridge_remove(&dsi->bridge);
> > -	component_del(&pdev->dev, &mtk_dsi_component_ops);
> >  	mipi_dsi_host_unregister(&dsi->host);
> >  
> >  	return 0;


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Re: [PATCH v4] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[CK Hu]

Hi, Angelo:

On Tue, 2022-02-08 at 16:20 +0800, CK Hu wrote:
> Hi, Angelo:
> 
> On Mon, 2022-01-31 at 09:55 +0100, AngeloGioacchino Del Regno wrote:
> > DRM bridge drivers are now attaching their DSI device at probe
> > time,
> > which requires us to register our DSI host in order to let the
> > bridge
> > to probe: this recently started producing an endless -EPROBE_DEFER
> > loop on some machines that are using external bridges, like the
> > parade-ps8640, found on the ACER Chromebook R13.
> > 
> > Now that the DSI hosts/devices probe sequence is documented, we can
> > do adjustments to the mtk_dsi driver as to both fix now and make
> > sure
> > to avoid this situation in the future: for this, following what is
> > documented in drm_bridge.c, move the mtk_dsi component_add() to the
> > mtk_dsi_ops.attach callback and delete it in the detach callback;
> > keeping in mind that we are registering a drm_bridge for our DSI,
> > which is only used/attached if the DSI Host is bound, it wouldn't
> > make sense to keep adding our bridge at probe time (as it would
> > be useless to have it if mtk_dsi_ops.attach() fails!), so also move
> > that one to the dsi host attach function (and remove it in detach).
> > 
> > Cc: <stable@vger.kernel.org> # 5.15.x
> > Signed-off-by: AngeloGioacchino Del Regno <
> > angelogioacchino.delregno@collabora.com>
> > Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
> > Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
> > 
> > ---
> >  drivers/gpu/drm/mediatek/mtk_dsi.c | 167 +++++++++++++++----------
> > ----
> >  1 file changed, 84 insertions(+), 83 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c
> > b/drivers/gpu/drm/mediatek/mtk_dsi.c
> > index 5d90d2eb0019..bced4c7d668e 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> > @@ -786,18 +786,101 @@ void mtk_dsi_ddp_stop(struct device *dev)
> >  	mtk_dsi_poweroff(dsi);
> >  }
> >  
> > 
> 
> [snip]
> 
> > +
> >  static int mtk_dsi_host_attach(struct mipi_dsi_host *host,
> >  			       struct mipi_dsi_device *device)
> >  {
> >  	struct mtk_dsi *dsi = host_to_dsi(host);
> > +	struct device *dev = host->dev;
> > +	int ret;
> >  
> >  	dsi->lanes = device->lanes;
> >  	dsi->format = device->format;
> >  	dsi->mode_flags = device->mode_flags;
> > +	dsi->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0,
> > 0);
> 
> The original would process panel. Why do you remove the panel part?
> It's better that someone has a platform of DSI->Panel to test this
> patch.

Sorry, devm_drm_of_get_bridge() has processed the panel part, so for
this patch,

Reviewed-by: CK Hu <ck.hu@mediatek.com>

> 
> Regards,
> CK
> 
> > +	if (IS_ERR(dsi->next_bridge))
> > +		return PTR_ERR(dsi->next_bridge);
> > +
> > +	drm_bridge_add(&dsi->bridge);
> > +
> > +	ret = component_add(host->dev, &mtk_dsi_component_ops);
> > +	if (ret) {
> > +		DRM_ERROR("failed to add dsi_host component: %d\n",
> > ret);
> > +		drm_bridge_remove(&dsi->bridge);
> > +		return ret;
> > +	}
> >  
> >  	return 0;
> >  }
> >  
> > +static int mtk_dsi_host_detach(struct mipi_dsi_host *host,
> > +			       struct mipi_dsi_device *device)
> > +{
> > +	struct mtk_dsi *dsi = host_to_dsi(host);
> > +
> > +	component_del(host->dev, &mtk_dsi_component_ops);
> > +	drm_bridge_remove(&dsi->bridge);
> > +	return 0;
> > +}
> > +
> >  static void mtk_dsi_wait_for_idle(struct mtk_dsi *dsi)
> >  {
> >  	int ret;
> > @@ -938,73 +1021,14 @@ static ssize_t mtk_dsi_host_transfer(struct
> > mipi_dsi_host *host,
> >  
> >  static const struct mipi_dsi_host_ops mtk_dsi_ops = {
> >  	.attach = mtk_dsi_host_attach,
> > +	.detach = mtk_dsi_host_detach,
> >  	.transfer = mtk_dsi_host_transfer,
> >  };
> >  
> > 
> 
> [snip]
> 
> > -
> >  static int mtk_dsi_probe(struct platform_device *pdev)
> >  {
> >  	struct mtk_dsi *dsi;
> >  	struct device *dev = &pdev->dev;
> > -	struct drm_panel *panel;
> >  	struct resource *regs;
> >  	int irq_num;
> >  	int ret;
> > @@ -1021,19 +1045,6 @@ static int mtk_dsi_probe(struct
> > platform_device *pdev)
> >  		return ret;
> >  	}
> >  
> > -	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0,
> > -					  &panel, &dsi->next_bridge);
> > -	if (ret)
> > -		goto err_unregister_host;
> > -
> > -	if (panel) {
> > -		dsi->next_bridge = devm_drm_panel_bridge_add(dev,
> > panel);
> > -		if (IS_ERR(dsi->next_bridge)) {
> > -			ret = PTR_ERR(dsi->next_bridge);
> > -			goto err_unregister_host;
> > -		}
> > -	}
> > -
> >  	dsi->driver_data = of_device_get_match_data(dev);
> >  
> >  	dsi->engine_clk = devm_clk_get(dev, "engine");
> > @@ -1098,14 +1109,6 @@ static int mtk_dsi_probe(struct
> > platform_device *pdev)
> >  	dsi->bridge.of_node = dev->of_node;
> >  	dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
> >  
> > -	drm_bridge_add(&dsi->bridge);
> > -
> > -	ret = component_add(&pdev->dev, &mtk_dsi_component_ops);
> > -	if (ret) {
> > -		dev_err(&pdev->dev, "failed to add component: %d\n",
> > ret);
> > -		goto err_unregister_host;
> > -	}
> > -
> >  	return 0;
> >  
> >  err_unregister_host:
> > @@ -1118,8 +1121,6 @@ static int mtk_dsi_remove(struct
> > platform_device *pdev)
> >  	struct mtk_dsi *dsi = platform_get_drvdata(pdev);
> >  
> >  	mtk_output_dsi_disable(dsi);
> > -	drm_bridge_remove(&dsi->bridge);
> > -	component_del(&pdev->dev, &mtk_dsi_component_ops);
> >  	mipi_dsi_host_unregister(&dsi->host);
> >  
> >  	return 0;

Re: [PATCH v4] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[CK Hu]

Hi, Angelo:

On Tue, 2022-02-08 at 16:20 +0800, CK Hu wrote:
> Hi, Angelo:
> 
> On Mon, 2022-01-31 at 09:55 +0100, AngeloGioacchino Del Regno wrote:
> > DRM bridge drivers are now attaching their DSI device at probe
> > time,
> > which requires us to register our DSI host in order to let the
> > bridge
> > to probe: this recently started producing an endless -EPROBE_DEFER
> > loop on some machines that are using external bridges, like the
> > parade-ps8640, found on the ACER Chromebook R13.
> > 
> > Now that the DSI hosts/devices probe sequence is documented, we can
> > do adjustments to the mtk_dsi driver as to both fix now and make
> > sure
> > to avoid this situation in the future: for this, following what is
> > documented in drm_bridge.c, move the mtk_dsi component_add() to the
> > mtk_dsi_ops.attach callback and delete it in the detach callback;
> > keeping in mind that we are registering a drm_bridge for our DSI,
> > which is only used/attached if the DSI Host is bound, it wouldn't
> > make sense to keep adding our bridge at probe time (as it would
> > be useless to have it if mtk_dsi_ops.attach() fails!), so also move
> > that one to the dsi host attach function (and remove it in detach).
> > 
> > Cc: <stable@vger.kernel.org> # 5.15.x
> > Signed-off-by: AngeloGioacchino Del Regno <
> > angelogioacchino.delregno@collabora.com>
> > Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
> > Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
> > 
> > ---
> >  drivers/gpu/drm/mediatek/mtk_dsi.c | 167 +++++++++++++++----------
> > ----
> >  1 file changed, 84 insertions(+), 83 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c
> > b/drivers/gpu/drm/mediatek/mtk_dsi.c
> > index 5d90d2eb0019..bced4c7d668e 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> > @@ -786,18 +786,101 @@ void mtk_dsi_ddp_stop(struct device *dev)
> >  	mtk_dsi_poweroff(dsi);
> >  }
> >  
> > 
> 
> [snip]
> 
> > +
> >  static int mtk_dsi_host_attach(struct mipi_dsi_host *host,
> >  			       struct mipi_dsi_device *device)
> >  {
> >  	struct mtk_dsi *dsi = host_to_dsi(host);
> > +	struct device *dev = host->dev;
> > +	int ret;
> >  
> >  	dsi->lanes = device->lanes;
> >  	dsi->format = device->format;
> >  	dsi->mode_flags = device->mode_flags;
> > +	dsi->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0,
> > 0);
> 
> The original would process panel. Why do you remove the panel part?
> It's better that someone has a platform of DSI->Panel to test this
> patch.

Sorry, devm_drm_of_get_bridge() has processed the panel part, so for
this patch,

Reviewed-by: CK Hu <ck.hu@mediatek.com>

> 
> Regards,
> CK
> 
> > +	if (IS_ERR(dsi->next_bridge))
> > +		return PTR_ERR(dsi->next_bridge);
> > +
> > +	drm_bridge_add(&dsi->bridge);
> > +
> > +	ret = component_add(host->dev, &mtk_dsi_component_ops);
> > +	if (ret) {
> > +		DRM_ERROR("failed to add dsi_host component: %d\n",
> > ret);
> > +		drm_bridge_remove(&dsi->bridge);
> > +		return ret;
> > +	}
> >  
> >  	return 0;
> >  }
> >  
> > +static int mtk_dsi_host_detach(struct mipi_dsi_host *host,
> > +			       struct mipi_dsi_device *device)
> > +{
> > +	struct mtk_dsi *dsi = host_to_dsi(host);
> > +
> > +	component_del(host->dev, &mtk_dsi_component_ops);
> > +	drm_bridge_remove(&dsi->bridge);
> > +	return 0;
> > +}
> > +
> >  static void mtk_dsi_wait_for_idle(struct mtk_dsi *dsi)
> >  {
> >  	int ret;
> > @@ -938,73 +1021,14 @@ static ssize_t mtk_dsi_host_transfer(struct
> > mipi_dsi_host *host,
> >  
> >  static const struct mipi_dsi_host_ops mtk_dsi_ops = {
> >  	.attach = mtk_dsi_host_attach,
> > +	.detach = mtk_dsi_host_detach,
> >  	.transfer = mtk_dsi_host_transfer,
> >  };
> >  
> > 
> 
> [snip]
> 
> > -
> >  static int mtk_dsi_probe(struct platform_device *pdev)
> >  {
> >  	struct mtk_dsi *dsi;
> >  	struct device *dev = &pdev->dev;
> > -	struct drm_panel *panel;
> >  	struct resource *regs;
> >  	int irq_num;
> >  	int ret;
> > @@ -1021,19 +1045,6 @@ static int mtk_dsi_probe(struct
> > platform_device *pdev)
> >  		return ret;
> >  	}
> >  
> > -	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0,
> > -					  &panel, &dsi->next_bridge);
> > -	if (ret)
> > -		goto err_unregister_host;
> > -
> > -	if (panel) {
> > -		dsi->next_bridge = devm_drm_panel_bridge_add(dev,
> > panel);
> > -		if (IS_ERR(dsi->next_bridge)) {
> > -			ret = PTR_ERR(dsi->next_bridge);
> > -			goto err_unregister_host;
> > -		}
> > -	}
> > -
> >  	dsi->driver_data = of_device_get_match_data(dev);
> >  
> >  	dsi->engine_clk = devm_clk_get(dev, "engine");
> > @@ -1098,14 +1109,6 @@ static int mtk_dsi_probe(struct
> > platform_device *pdev)
> >  	dsi->bridge.of_node = dev->of_node;
> >  	dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
> >  
> > -	drm_bridge_add(&dsi->bridge);
> > -
> > -	ret = component_add(&pdev->dev, &mtk_dsi_component_ops);
> > -	if (ret) {
> > -		dev_err(&pdev->dev, "failed to add component: %d\n",
> > ret);
> > -		goto err_unregister_host;
> > -	}
> > -
> >  	return 0;
> >  
> >  err_unregister_host:
> > @@ -1118,8 +1121,6 @@ static int mtk_dsi_remove(struct
> > platform_device *pdev)
> >  	struct mtk_dsi *dsi = platform_get_drvdata(pdev);
> >  
> >  	mtk_output_dsi_disable(dsi);
> > -	drm_bridge_remove(&dsi->bridge);
> > -	component_del(&pdev->dev, &mtk_dsi_component_ops);
> >  	mipi_dsi_host_unregister(&dsi->host);
> >  
> >  	return 0;


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Re: [PATCH v4] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[AngeloGioacchino Del Regno]

Il 08/02/22 09:32, CK Hu ha scritto:
> Hi, Angelo:
> 
> On Tue, 2022-02-08 at 16:20 +0800, CK Hu wrote:
>> Hi, Angelo:
>>
>> On Mon, 2022-01-31 at 09:55 +0100, AngeloGioacchino Del Regno wrote:
>>> DRM bridge drivers are now attaching their DSI device at probe
>>> time,
>>> which requires us to register our DSI host in order to let the
>>> bridge
>>> to probe: this recently started producing an endless -EPROBE_DEFER
>>> loop on some machines that are using external bridges, like the
>>> parade-ps8640, found on the ACER Chromebook R13.
>>>
>>> Now that the DSI hosts/devices probe sequence is documented, we can
>>> do adjustments to the mtk_dsi driver as to both fix now and make
>>> sure
>>> to avoid this situation in the future: for this, following what is
>>> documented in drm_bridge.c, move the mtk_dsi component_add() to the
>>> mtk_dsi_ops.attach callback and delete it in the detach callback;
>>> keeping in mind that we are registering a drm_bridge for our DSI,
>>> which is only used/attached if the DSI Host is bound, it wouldn't
>>> make sense to keep adding our bridge at probe time (as it would
>>> be useless to have it if mtk_dsi_ops.attach() fails!), so also move
>>> that one to the dsi host attach function (and remove it in detach).
>>>
>>> Cc: <stable@vger.kernel.org> # 5.15.x
>>> Signed-off-by: AngeloGioacchino Del Regno <
>>> angelogioacchino.delregno@collabora.com>
>>> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
>>> Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
>>>
>>> ---
>>>   drivers/gpu/drm/mediatek/mtk_dsi.c | 167 +++++++++++++++----------
>>> ----
>>>   1 file changed, 84 insertions(+), 83 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c
>>> b/drivers/gpu/drm/mediatek/mtk_dsi.c
>>> index 5d90d2eb0019..bced4c7d668e 100644
>>> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
>>> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
>>> @@ -786,18 +786,101 @@ void mtk_dsi_ddp_stop(struct device *dev)
>>>   	mtk_dsi_poweroff(dsi);
>>>   }
>>>   
>>>
>>
>> [snip]
>>
>>> +
>>>   static int mtk_dsi_host_attach(struct mipi_dsi_host *host,
>>>   			       struct mipi_dsi_device *device)
>>>   {
>>>   	struct mtk_dsi *dsi = host_to_dsi(host);
>>> +	struct device *dev = host->dev;
>>> +	int ret;
>>>   
>>>   	dsi->lanes = device->lanes;
>>>   	dsi->format = device->format;
>>>   	dsi->mode_flags = device->mode_flags;
>>> +	dsi->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0,
>>> 0);
>>
>> The original would process panel. Why do you remove the panel part?
>> It's better that someone has a platform of DSI->Panel to test this
>> patch.
> 
> Sorry, devm_drm_of_get_bridge() has processed the panel part, so for
> this patch,
> 
> Reviewed-by: CK Hu <ck.hu@mediatek.com>
> 

No worries! Thanks for the review/approval.

Regards,
Angelo

>>
>> Regards,
>> CK
>>

Re: [PATCH v4] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[AngeloGioacchino Del Regno]

Il 08/02/22 09:32, CK Hu ha scritto:
> Hi, Angelo:
> 
> On Tue, 2022-02-08 at 16:20 +0800, CK Hu wrote:
>> Hi, Angelo:
>>
>> On Mon, 2022-01-31 at 09:55 +0100, AngeloGioacchino Del Regno wrote:
>>> DRM bridge drivers are now attaching their DSI device at probe
>>> time,
>>> which requires us to register our DSI host in order to let the
>>> bridge
>>> to probe: this recently started producing an endless -EPROBE_DEFER
>>> loop on some machines that are using external bridges, like the
>>> parade-ps8640, found on the ACER Chromebook R13.
>>>
>>> Now that the DSI hosts/devices probe sequence is documented, we can
>>> do adjustments to the mtk_dsi driver as to both fix now and make
>>> sure
>>> to avoid this situation in the future: for this, following what is
>>> documented in drm_bridge.c, move the mtk_dsi component_add() to the
>>> mtk_dsi_ops.attach callback and delete it in the detach callback;
>>> keeping in mind that we are registering a drm_bridge for our DSI,
>>> which is only used/attached if the DSI Host is bound, it wouldn't
>>> make sense to keep adding our bridge at probe time (as it would
>>> be useless to have it if mtk_dsi_ops.attach() fails!), so also move
>>> that one to the dsi host attach function (and remove it in detach).
>>>
>>> Cc: <stable@vger.kernel.org> # 5.15.x
>>> Signed-off-by: AngeloGioacchino Del Regno <
>>> angelogioacchino.delregno@collabora.com>
>>> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
>>> Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
>>>
>>> ---
>>>   drivers/gpu/drm/mediatek/mtk_dsi.c | 167 +++++++++++++++----------
>>> ----
>>>   1 file changed, 84 insertions(+), 83 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c
>>> b/drivers/gpu/drm/mediatek/mtk_dsi.c
>>> index 5d90d2eb0019..bced4c7d668e 100644
>>> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
>>> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
>>> @@ -786,18 +786,101 @@ void mtk_dsi_ddp_stop(struct device *dev)
>>>   	mtk_dsi_poweroff(dsi);
>>>   }
>>>   
>>>
>>
>> [snip]
>>
>>> +
>>>   static int mtk_dsi_host_attach(struct mipi_dsi_host *host,
>>>   			       struct mipi_dsi_device *device)
>>>   {
>>>   	struct mtk_dsi *dsi = host_to_dsi(host);
>>> +	struct device *dev = host->dev;
>>> +	int ret;
>>>   
>>>   	dsi->lanes = device->lanes;
>>>   	dsi->format = device->format;
>>>   	dsi->mode_flags = device->mode_flags;
>>> +	dsi->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0,
>>> 0);
>>
>> The original would process panel. Why do you remove the panel part?
>> It's better that someone has a platform of DSI->Panel to test this
>> patch.
> 
> Sorry, devm_drm_of_get_bridge() has processed the panel part, so for
> this patch,
> 
> Reviewed-by: CK Hu <ck.hu@mediatek.com>
> 

No worries! Thanks for the review/approval.

Regards,
Angelo

>>
>> Regards,
>> CK
>>

Re: [PATCH v4] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[AngeloGioacchino Del Regno]

Il 08/02/22 09:32, CK Hu ha scritto:
> Hi, Angelo:
> 
> On Tue, 2022-02-08 at 16:20 +0800, CK Hu wrote:
>> Hi, Angelo:
>>
>> On Mon, 2022-01-31 at 09:55 +0100, AngeloGioacchino Del Regno wrote:
>>> DRM bridge drivers are now attaching their DSI device at probe
>>> time,
>>> which requires us to register our DSI host in order to let the
>>> bridge
>>> to probe: this recently started producing an endless -EPROBE_DEFER
>>> loop on some machines that are using external bridges, like the
>>> parade-ps8640, found on the ACER Chromebook R13.
>>>
>>> Now that the DSI hosts/devices probe sequence is documented, we can
>>> do adjustments to the mtk_dsi driver as to both fix now and make
>>> sure
>>> to avoid this situation in the future: for this, following what is
>>> documented in drm_bridge.c, move the mtk_dsi component_add() to the
>>> mtk_dsi_ops.attach callback and delete it in the detach callback;
>>> keeping in mind that we are registering a drm_bridge for our DSI,
>>> which is only used/attached if the DSI Host is bound, it wouldn't
>>> make sense to keep adding our bridge at probe time (as it would
>>> be useless to have it if mtk_dsi_ops.attach() fails!), so also move
>>> that one to the dsi host attach function (and remove it in detach).
>>>
>>> Cc: <stable@vger.kernel.org> # 5.15.x
>>> Signed-off-by: AngeloGioacchino Del Regno <
>>> angelogioacchino.delregno@collabora.com>
>>> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
>>> Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
>>>
>>> ---
>>>   drivers/gpu/drm/mediatek/mtk_dsi.c | 167 +++++++++++++++----------
>>> ----
>>>   1 file changed, 84 insertions(+), 83 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c
>>> b/drivers/gpu/drm/mediatek/mtk_dsi.c
>>> index 5d90d2eb0019..bced4c7d668e 100644
>>> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
>>> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
>>> @@ -786,18 +786,101 @@ void mtk_dsi_ddp_stop(struct device *dev)
>>>   	mtk_dsi_poweroff(dsi);
>>>   }
>>>   
>>>
>>
>> [snip]
>>
>>> +
>>>   static int mtk_dsi_host_attach(struct mipi_dsi_host *host,
>>>   			       struct mipi_dsi_device *device)
>>>   {
>>>   	struct mtk_dsi *dsi = host_to_dsi(host);
>>> +	struct device *dev = host->dev;
>>> +	int ret;
>>>   
>>>   	dsi->lanes = device->lanes;
>>>   	dsi->format = device->format;
>>>   	dsi->mode_flags = device->mode_flags;
>>> +	dsi->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0,
>>> 0);
>>
>> The original would process panel. Why do you remove the panel part?
>> It's better that someone has a platform of DSI->Panel to test this
>> patch.
> 
> Sorry, devm_drm_of_get_bridge() has processed the panel part, so for
> this patch,
> 
> Reviewed-by: CK Hu <ck.hu@mediatek.com>
> 

No worries! Thanks for the review/approval.

Regards,
Angelo

>>
>> Regards,
>> CK
>>

_______________________________________________
Linux-mediatek mailing list
Linux-mediatek@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-mediatek

Re: [PATCH v4] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[AngeloGioacchino Del Regno]

Il 08/02/22 09:32, CK Hu ha scritto:
> Hi, Angelo:
> 
> On Tue, 2022-02-08 at 16:20 +0800, CK Hu wrote:
>> Hi, Angelo:
>>
>> On Mon, 2022-01-31 at 09:55 +0100, AngeloGioacchino Del Regno wrote:
>>> DRM bridge drivers are now attaching their DSI device at probe
>>> time,
>>> which requires us to register our DSI host in order to let the
>>> bridge
>>> to probe: this recently started producing an endless -EPROBE_DEFER
>>> loop on some machines that are using external bridges, like the
>>> parade-ps8640, found on the ACER Chromebook R13.
>>>
>>> Now that the DSI hosts/devices probe sequence is documented, we can
>>> do adjustments to the mtk_dsi driver as to both fix now and make
>>> sure
>>> to avoid this situation in the future: for this, following what is
>>> documented in drm_bridge.c, move the mtk_dsi component_add() to the
>>> mtk_dsi_ops.attach callback and delete it in the detach callback;
>>> keeping in mind that we are registering a drm_bridge for our DSI,
>>> which is only used/attached if the DSI Host is bound, it wouldn't
>>> make sense to keep adding our bridge at probe time (as it would
>>> be useless to have it if mtk_dsi_ops.attach() fails!), so also move
>>> that one to the dsi host attach function (and remove it in detach).
>>>
>>> Cc: <stable@vger.kernel.org> # 5.15.x
>>> Signed-off-by: AngeloGioacchino Del Regno <
>>> angelogioacchino.delregno@collabora.com>
>>> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
>>> Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
>>>
>>> ---
>>>   drivers/gpu/drm/mediatek/mtk_dsi.c | 167 +++++++++++++++----------
>>> ----
>>>   1 file changed, 84 insertions(+), 83 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c
>>> b/drivers/gpu/drm/mediatek/mtk_dsi.c
>>> index 5d90d2eb0019..bced4c7d668e 100644
>>> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
>>> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
>>> @@ -786,18 +786,101 @@ void mtk_dsi_ddp_stop(struct device *dev)
>>>   	mtk_dsi_poweroff(dsi);
>>>   }
>>>   
>>>
>>
>> [snip]
>>
>>> +
>>>   static int mtk_dsi_host_attach(struct mipi_dsi_host *host,
>>>   			       struct mipi_dsi_device *device)
>>>   {
>>>   	struct mtk_dsi *dsi = host_to_dsi(host);
>>> +	struct device *dev = host->dev;
>>> +	int ret;
>>>   
>>>   	dsi->lanes = device->lanes;
>>>   	dsi->format = device->format;
>>>   	dsi->mode_flags = device->mode_flags;
>>> +	dsi->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0,
>>> 0);
>>
>> The original would process panel. Why do you remove the panel part?
>> It's better that someone has a platform of DSI->Panel to test this
>> patch.
> 
> Sorry, devm_drm_of_get_bridge() has processed the panel part, so for
> this patch,
> 
> Reviewed-by: CK Hu <ck.hu@mediatek.com>
> 

No worries! Thanks for the review/approval.

Regards,
Angelo

>>
>> Regards,
>> CK
>>

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH v4] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[Nícolas F. R. A. Prado]

Hi Angelo,

On Mon, Jan 31, 2022 at 09:55:20AM +0100, AngeloGioacchino Del Regno wrote:
> DRM bridge drivers are now attaching their DSI device at probe time,
> which requires us to register our DSI host in order to let the bridge
> to probe: this recently started producing an endless -EPROBE_DEFER
> loop on some machines that are using external bridges, like the
> parade-ps8640, found on the ACER Chromebook R13.
> 
> Now that the DSI hosts/devices probe sequence is documented, we can
> do adjustments to the mtk_dsi driver as to both fix now and make sure
> to avoid this situation in the future: for this, following what is
> documented in drm_bridge.c, move the mtk_dsi component_add() to the
> mtk_dsi_ops.attach callback and delete it in the detach callback;
> keeping in mind that we are registering a drm_bridge for our DSI,
> which is only used/attached if the DSI Host is bound, it wouldn't
> make sense to keep adding our bridge at probe time (as it would
> be useless to have it if mtk_dsi_ops.attach() fails!), so also move
> that one to the dsi host attach function (and remove it in detach).
> 
> Cc: <stable@vger.kernel.org> # 5.15.x
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
> Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>

Tested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>

Thanks,
Nícolas

> 
> ---
>  drivers/gpu/drm/mediatek/mtk_dsi.c | 167 +++++++++++++++--------------
>  1 file changed, 84 insertions(+), 83 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index 5d90d2eb0019..bced4c7d668e 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -786,18 +786,101 @@ void mtk_dsi_ddp_stop(struct device *dev)
>  	mtk_dsi_poweroff(dsi);
>  }
>  
> +static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi)
> +{
> +	int ret;
> +
> +	ret = drm_simple_encoder_init(drm, &dsi->encoder,
> +				      DRM_MODE_ENCODER_DSI);
> +	if (ret) {
> +		DRM_ERROR("Failed to encoder init to drm\n");
> +		return ret;
> +	}
> +
> +	dsi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
> +
> +	ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL,
> +				DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> +	if (ret)
> +		goto err_cleanup_encoder;
> +
> +	dsi->connector = drm_bridge_connector_init(drm, &dsi->encoder);
> +	if (IS_ERR(dsi->connector)) {
> +		DRM_ERROR("Unable to create bridge connector\n");
> +		ret = PTR_ERR(dsi->connector);
> +		goto err_cleanup_encoder;
> +	}
> +	drm_connector_attach_encoder(dsi->connector, &dsi->encoder);
> +
> +	return 0;
> +
> +err_cleanup_encoder:
> +	drm_encoder_cleanup(&dsi->encoder);
> +	return ret;
> +}
> +
> +static int mtk_dsi_bind(struct device *dev, struct device *master, void *data)
> +{
> +	int ret;
> +	struct drm_device *drm = data;
> +	struct mtk_dsi *dsi = dev_get_drvdata(dev);
> +
> +	ret = mtk_dsi_encoder_init(drm, dsi);
> +	if (ret)
> +		return ret;
> +
> +	return device_reset_optional(dev);
> +}
> +
> +static void mtk_dsi_unbind(struct device *dev, struct device *master,
> +			   void *data)
> +{
> +	struct mtk_dsi *dsi = dev_get_drvdata(dev);
> +
> +	drm_encoder_cleanup(&dsi->encoder);
> +}
> +
> +static const struct component_ops mtk_dsi_component_ops = {
> +	.bind = mtk_dsi_bind,
> +	.unbind = mtk_dsi_unbind,
> +};
> +
>  static int mtk_dsi_host_attach(struct mipi_dsi_host *host,
>  			       struct mipi_dsi_device *device)
>  {
>  	struct mtk_dsi *dsi = host_to_dsi(host);
> +	struct device *dev = host->dev;
> +	int ret;
>  
>  	dsi->lanes = device->lanes;
>  	dsi->format = device->format;
>  	dsi->mode_flags = device->mode_flags;
> +	dsi->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0);
> +	if (IS_ERR(dsi->next_bridge))
> +		return PTR_ERR(dsi->next_bridge);
> +
> +	drm_bridge_add(&dsi->bridge);
> +
> +	ret = component_add(host->dev, &mtk_dsi_component_ops);
> +	if (ret) {
> +		DRM_ERROR("failed to add dsi_host component: %d\n", ret);
> +		drm_bridge_remove(&dsi->bridge);
> +		return ret;
> +	}
>  
>  	return 0;
>  }
>  
> +static int mtk_dsi_host_detach(struct mipi_dsi_host *host,
> +			       struct mipi_dsi_device *device)
> +{
> +	struct mtk_dsi *dsi = host_to_dsi(host);
> +
> +	component_del(host->dev, &mtk_dsi_component_ops);
> +	drm_bridge_remove(&dsi->bridge);
> +	return 0;
> +}
> +
>  static void mtk_dsi_wait_for_idle(struct mtk_dsi *dsi)
>  {
>  	int ret;
> @@ -938,73 +1021,14 @@ static ssize_t mtk_dsi_host_transfer(struct mipi_dsi_host *host,
>  
>  static const struct mipi_dsi_host_ops mtk_dsi_ops = {
>  	.attach = mtk_dsi_host_attach,
> +	.detach = mtk_dsi_host_detach,
>  	.transfer = mtk_dsi_host_transfer,
>  };
>  
> -static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi)
> -{
> -	int ret;
> -
> -	ret = drm_simple_encoder_init(drm, &dsi->encoder,
> -				      DRM_MODE_ENCODER_DSI);
> -	if (ret) {
> -		DRM_ERROR("Failed to encoder init to drm\n");
> -		return ret;
> -	}
> -
> -	dsi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
> -
> -	ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL,
> -				DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> -	if (ret)
> -		goto err_cleanup_encoder;
> -
> -	dsi->connector = drm_bridge_connector_init(drm, &dsi->encoder);
> -	if (IS_ERR(dsi->connector)) {
> -		DRM_ERROR("Unable to create bridge connector\n");
> -		ret = PTR_ERR(dsi->connector);
> -		goto err_cleanup_encoder;
> -	}
> -	drm_connector_attach_encoder(dsi->connector, &dsi->encoder);
> -
> -	return 0;
> -
> -err_cleanup_encoder:
> -	drm_encoder_cleanup(&dsi->encoder);
> -	return ret;
> -}
> -
> -static int mtk_dsi_bind(struct device *dev, struct device *master, void *data)
> -{
> -	int ret;
> -	struct drm_device *drm = data;
> -	struct mtk_dsi *dsi = dev_get_drvdata(dev);
> -
> -	ret = mtk_dsi_encoder_init(drm, dsi);
> -	if (ret)
> -		return ret;
> -
> -	return device_reset_optional(dev);
> -}
> -
> -static void mtk_dsi_unbind(struct device *dev, struct device *master,
> -			   void *data)
> -{
> -	struct mtk_dsi *dsi = dev_get_drvdata(dev);
> -
> -	drm_encoder_cleanup(&dsi->encoder);
> -}
> -
> -static const struct component_ops mtk_dsi_component_ops = {
> -	.bind = mtk_dsi_bind,
> -	.unbind = mtk_dsi_unbind,
> -};
> -
>  static int mtk_dsi_probe(struct platform_device *pdev)
>  {
>  	struct mtk_dsi *dsi;
>  	struct device *dev = &pdev->dev;
> -	struct drm_panel *panel;
>  	struct resource *regs;
>  	int irq_num;
>  	int ret;
> @@ -1021,19 +1045,6 @@ static int mtk_dsi_probe(struct platform_device *pdev)
>  		return ret;
>  	}
>  
> -	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0,
> -					  &panel, &dsi->next_bridge);
> -	if (ret)
> -		goto err_unregister_host;
> -
> -	if (panel) {
> -		dsi->next_bridge = devm_drm_panel_bridge_add(dev, panel);
> -		if (IS_ERR(dsi->next_bridge)) {
> -			ret = PTR_ERR(dsi->next_bridge);
> -			goto err_unregister_host;
> -		}
> -	}
> -
>  	dsi->driver_data = of_device_get_match_data(dev);
>  
>  	dsi->engine_clk = devm_clk_get(dev, "engine");
> @@ -1098,14 +1109,6 @@ static int mtk_dsi_probe(struct platform_device *pdev)
>  	dsi->bridge.of_node = dev->of_node;
>  	dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
>  
> -	drm_bridge_add(&dsi->bridge);
> -
> -	ret = component_add(&pdev->dev, &mtk_dsi_component_ops);
> -	if (ret) {
> -		dev_err(&pdev->dev, "failed to add component: %d\n", ret);
> -		goto err_unregister_host;
> -	}
> -
>  	return 0;
>  
>  err_unregister_host:
> @@ -1118,8 +1121,6 @@ static int mtk_dsi_remove(struct platform_device *pdev)
>  	struct mtk_dsi *dsi = platform_get_drvdata(pdev);
>  
>  	mtk_output_dsi_disable(dsi);
> -	drm_bridge_remove(&dsi->bridge);
> -	component_del(&pdev->dev, &mtk_dsi_component_ops);
>  	mipi_dsi_host_unregister(&dsi->host);
>  
>  	return 0;
> -- 
> 2.33.1
> 
> 
> -- 
> To unsubscribe, send mail to kernel-unsubscribe@lists.collabora.co.uk.

Re: [PATCH v4] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[Nícolas F. R. A. Prado]

Hi Angelo,

On Mon, Jan 31, 2022 at 09:55:20AM +0100, AngeloGioacchino Del Regno wrote:
> DRM bridge drivers are now attaching their DSI device at probe time,
> which requires us to register our DSI host in order to let the bridge
> to probe: this recently started producing an endless -EPROBE_DEFER
> loop on some machines that are using external bridges, like the
> parade-ps8640, found on the ACER Chromebook R13.
> 
> Now that the DSI hosts/devices probe sequence is documented, we can
> do adjustments to the mtk_dsi driver as to both fix now and make sure
> to avoid this situation in the future: for this, following what is
> documented in drm_bridge.c, move the mtk_dsi component_add() to the
> mtk_dsi_ops.attach callback and delete it in the detach callback;
> keeping in mind that we are registering a drm_bridge for our DSI,
> which is only used/attached if the DSI Host is bound, it wouldn't
> make sense to keep adding our bridge at probe time (as it would
> be useless to have it if mtk_dsi_ops.attach() fails!), so also move
> that one to the dsi host attach function (and remove it in detach).
> 
> Cc: <stable@vger.kernel.org> # 5.15.x
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
> Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>

Tested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>

Thanks,
Nícolas

> 
> ---
>  drivers/gpu/drm/mediatek/mtk_dsi.c | 167 +++++++++++++++--------------
>  1 file changed, 84 insertions(+), 83 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index 5d90d2eb0019..bced4c7d668e 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -786,18 +786,101 @@ void mtk_dsi_ddp_stop(struct device *dev)
>  	mtk_dsi_poweroff(dsi);
>  }
>  
> +static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi)
> +{
> +	int ret;
> +
> +	ret = drm_simple_encoder_init(drm, &dsi->encoder,
> +				      DRM_MODE_ENCODER_DSI);
> +	if (ret) {
> +		DRM_ERROR("Failed to encoder init to drm\n");
> +		return ret;
> +	}
> +
> +	dsi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
> +
> +	ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL,
> +				DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> +	if (ret)
> +		goto err_cleanup_encoder;
> +
> +	dsi->connector = drm_bridge_connector_init(drm, &dsi->encoder);
> +	if (IS_ERR(dsi->connector)) {
> +		DRM_ERROR("Unable to create bridge connector\n");
> +		ret = PTR_ERR(dsi->connector);
> +		goto err_cleanup_encoder;
> +	}
> +	drm_connector_attach_encoder(dsi->connector, &dsi->encoder);
> +
> +	return 0;
> +
> +err_cleanup_encoder:
> +	drm_encoder_cleanup(&dsi->encoder);
> +	return ret;
> +}
> +
> +static int mtk_dsi_bind(struct device *dev, struct device *master, void *data)
> +{
> +	int ret;
> +	struct drm_device *drm = data;
> +	struct mtk_dsi *dsi = dev_get_drvdata(dev);
> +
> +	ret = mtk_dsi_encoder_init(drm, dsi);
> +	if (ret)
> +		return ret;
> +
> +	return device_reset_optional(dev);
> +}
> +
> +static void mtk_dsi_unbind(struct device *dev, struct device *master,
> +			   void *data)
> +{
> +	struct mtk_dsi *dsi = dev_get_drvdata(dev);
> +
> +	drm_encoder_cleanup(&dsi->encoder);
> +}
> +
> +static const struct component_ops mtk_dsi_component_ops = {
> +	.bind = mtk_dsi_bind,
> +	.unbind = mtk_dsi_unbind,
> +};
> +
>  static int mtk_dsi_host_attach(struct mipi_dsi_host *host,
>  			       struct mipi_dsi_device *device)
>  {
>  	struct mtk_dsi *dsi = host_to_dsi(host);
> +	struct device *dev = host->dev;
> +	int ret;
>  
>  	dsi->lanes = device->lanes;
>  	dsi->format = device->format;
>  	dsi->mode_flags = device->mode_flags;
> +	dsi->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0);
> +	if (IS_ERR(dsi->next_bridge))
> +		return PTR_ERR(dsi->next_bridge);
> +
> +	drm_bridge_add(&dsi->bridge);
> +
> +	ret = component_add(host->dev, &mtk_dsi_component_ops);
> +	if (ret) {
> +		DRM_ERROR("failed to add dsi_host component: %d\n", ret);
> +		drm_bridge_remove(&dsi->bridge);
> +		return ret;
> +	}
>  
>  	return 0;
>  }
>  
> +static int mtk_dsi_host_detach(struct mipi_dsi_host *host,
> +			       struct mipi_dsi_device *device)
> +{
> +	struct mtk_dsi *dsi = host_to_dsi(host);
> +
> +	component_del(host->dev, &mtk_dsi_component_ops);
> +	drm_bridge_remove(&dsi->bridge);
> +	return 0;
> +}
> +
>  static void mtk_dsi_wait_for_idle(struct mtk_dsi *dsi)
>  {
>  	int ret;
> @@ -938,73 +1021,14 @@ static ssize_t mtk_dsi_host_transfer(struct mipi_dsi_host *host,
>  
>  static const struct mipi_dsi_host_ops mtk_dsi_ops = {
>  	.attach = mtk_dsi_host_attach,
> +	.detach = mtk_dsi_host_detach,
>  	.transfer = mtk_dsi_host_transfer,
>  };
>  
> -static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi)
> -{
> -	int ret;
> -
> -	ret = drm_simple_encoder_init(drm, &dsi->encoder,
> -				      DRM_MODE_ENCODER_DSI);
> -	if (ret) {
> -		DRM_ERROR("Failed to encoder init to drm\n");
> -		return ret;
> -	}
> -
> -	dsi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
> -
> -	ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL,
> -				DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> -	if (ret)
> -		goto err_cleanup_encoder;
> -
> -	dsi->connector = drm_bridge_connector_init(drm, &dsi->encoder);
> -	if (IS_ERR(dsi->connector)) {
> -		DRM_ERROR("Unable to create bridge connector\n");
> -		ret = PTR_ERR(dsi->connector);
> -		goto err_cleanup_encoder;
> -	}
> -	drm_connector_attach_encoder(dsi->connector, &dsi->encoder);
> -
> -	return 0;
> -
> -err_cleanup_encoder:
> -	drm_encoder_cleanup(&dsi->encoder);
> -	return ret;
> -}
> -
> -static int mtk_dsi_bind(struct device *dev, struct device *master, void *data)
> -{
> -	int ret;
> -	struct drm_device *drm = data;
> -	struct mtk_dsi *dsi = dev_get_drvdata(dev);
> -
> -	ret = mtk_dsi_encoder_init(drm, dsi);
> -	if (ret)
> -		return ret;
> -
> -	return device_reset_optional(dev);
> -}
> -
> -static void mtk_dsi_unbind(struct device *dev, struct device *master,
> -			   void *data)
> -{
> -	struct mtk_dsi *dsi = dev_get_drvdata(dev);
> -
> -	drm_encoder_cleanup(&dsi->encoder);
> -}
> -
> -static const struct component_ops mtk_dsi_component_ops = {
> -	.bind = mtk_dsi_bind,
> -	.unbind = mtk_dsi_unbind,
> -};
> -
>  static int mtk_dsi_probe(struct platform_device *pdev)
>  {
>  	struct mtk_dsi *dsi;
>  	struct device *dev = &pdev->dev;
> -	struct drm_panel *panel;
>  	struct resource *regs;
>  	int irq_num;
>  	int ret;
> @@ -1021,19 +1045,6 @@ static int mtk_dsi_probe(struct platform_device *pdev)
>  		return ret;
>  	}
>  
> -	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0,
> -					  &panel, &dsi->next_bridge);
> -	if (ret)
> -		goto err_unregister_host;
> -
> -	if (panel) {
> -		dsi->next_bridge = devm_drm_panel_bridge_add(dev, panel);
> -		if (IS_ERR(dsi->next_bridge)) {
> -			ret = PTR_ERR(dsi->next_bridge);
> -			goto err_unregister_host;
> -		}
> -	}
> -
>  	dsi->driver_data = of_device_get_match_data(dev);
>  
>  	dsi->engine_clk = devm_clk_get(dev, "engine");
> @@ -1098,14 +1109,6 @@ static int mtk_dsi_probe(struct platform_device *pdev)
>  	dsi->bridge.of_node = dev->of_node;
>  	dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
>  
> -	drm_bridge_add(&dsi->bridge);
> -
> -	ret = component_add(&pdev->dev, &mtk_dsi_component_ops);
> -	if (ret) {
> -		dev_err(&pdev->dev, "failed to add component: %d\n", ret);
> -		goto err_unregister_host;
> -	}
> -
>  	return 0;
>  
>  err_unregister_host:
> @@ -1118,8 +1121,6 @@ static int mtk_dsi_remove(struct platform_device *pdev)
>  	struct mtk_dsi *dsi = platform_get_drvdata(pdev);
>  
>  	mtk_output_dsi_disable(dsi);
> -	drm_bridge_remove(&dsi->bridge);
> -	component_del(&pdev->dev, &mtk_dsi_component_ops);
>  	mipi_dsi_host_unregister(&dsi->host);
>  
>  	return 0;
> -- 
> 2.33.1
> 
> 
> -- 
> To unsubscribe, send mail to kernel-unsubscribe@lists.collabora.co.uk.

Re: [PATCH v4] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[Nícolas F. R. A. Prado]

Hi Angelo,

On Mon, Jan 31, 2022 at 09:55:20AM +0100, AngeloGioacchino Del Regno wrote:
> DRM bridge drivers are now attaching their DSI device at probe time,
> which requires us to register our DSI host in order to let the bridge
> to probe: this recently started producing an endless -EPROBE_DEFER
> loop on some machines that are using external bridges, like the
> parade-ps8640, found on the ACER Chromebook R13.
> 
> Now that the DSI hosts/devices probe sequence is documented, we can
> do adjustments to the mtk_dsi driver as to both fix now and make sure
> to avoid this situation in the future: for this, following what is
> documented in drm_bridge.c, move the mtk_dsi component_add() to the
> mtk_dsi_ops.attach callback and delete it in the detach callback;
> keeping in mind that we are registering a drm_bridge for our DSI,
> which is only used/attached if the DSI Host is bound, it wouldn't
> make sense to keep adding our bridge at probe time (as it would
> be useless to have it if mtk_dsi_ops.attach() fails!), so also move
> that one to the dsi host attach function (and remove it in detach).
> 
> Cc: <stable@vger.kernel.org> # 5.15.x
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
> Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>

Tested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>

Thanks,
Nícolas

> 
> ---
>  drivers/gpu/drm/mediatek/mtk_dsi.c | 167 +++++++++++++++--------------
>  1 file changed, 84 insertions(+), 83 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index 5d90d2eb0019..bced4c7d668e 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -786,18 +786,101 @@ void mtk_dsi_ddp_stop(struct device *dev)
>  	mtk_dsi_poweroff(dsi);
>  }
>  
> +static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi)
> +{
> +	int ret;
> +
> +	ret = drm_simple_encoder_init(drm, &dsi->encoder,
> +				      DRM_MODE_ENCODER_DSI);
> +	if (ret) {
> +		DRM_ERROR("Failed to encoder init to drm\n");
> +		return ret;
> +	}
> +
> +	dsi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
> +
> +	ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL,
> +				DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> +	if (ret)
> +		goto err_cleanup_encoder;
> +
> +	dsi->connector = drm_bridge_connector_init(drm, &dsi->encoder);
> +	if (IS_ERR(dsi->connector)) {
> +		DRM_ERROR("Unable to create bridge connector\n");
> +		ret = PTR_ERR(dsi->connector);
> +		goto err_cleanup_encoder;
> +	}
> +	drm_connector_attach_encoder(dsi->connector, &dsi->encoder);
> +
> +	return 0;
> +
> +err_cleanup_encoder:
> +	drm_encoder_cleanup(&dsi->encoder);
> +	return ret;
> +}
> +
> +static int mtk_dsi_bind(struct device *dev, struct device *master, void *data)
> +{
> +	int ret;
> +	struct drm_device *drm = data;
> +	struct mtk_dsi *dsi = dev_get_drvdata(dev);
> +
> +	ret = mtk_dsi_encoder_init(drm, dsi);
> +	if (ret)
> +		return ret;
> +
> +	return device_reset_optional(dev);
> +}
> +
> +static void mtk_dsi_unbind(struct device *dev, struct device *master,
> +			   void *data)
> +{
> +	struct mtk_dsi *dsi = dev_get_drvdata(dev);
> +
> +	drm_encoder_cleanup(&dsi->encoder);
> +}
> +
> +static const struct component_ops mtk_dsi_component_ops = {
> +	.bind = mtk_dsi_bind,
> +	.unbind = mtk_dsi_unbind,
> +};
> +
>  static int mtk_dsi_host_attach(struct mipi_dsi_host *host,
>  			       struct mipi_dsi_device *device)
>  {
>  	struct mtk_dsi *dsi = host_to_dsi(host);
> +	struct device *dev = host->dev;
> +	int ret;
>  
>  	dsi->lanes = device->lanes;
>  	dsi->format = device->format;
>  	dsi->mode_flags = device->mode_flags;
> +	dsi->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0);
> +	if (IS_ERR(dsi->next_bridge))
> +		return PTR_ERR(dsi->next_bridge);
> +
> +	drm_bridge_add(&dsi->bridge);
> +
> +	ret = component_add(host->dev, &mtk_dsi_component_ops);
> +	if (ret) {
> +		DRM_ERROR("failed to add dsi_host component: %d\n", ret);
> +		drm_bridge_remove(&dsi->bridge);
> +		return ret;
> +	}
>  
>  	return 0;
>  }
>  
> +static int mtk_dsi_host_detach(struct mipi_dsi_host *host,
> +			       struct mipi_dsi_device *device)
> +{
> +	struct mtk_dsi *dsi = host_to_dsi(host);
> +
> +	component_del(host->dev, &mtk_dsi_component_ops);
> +	drm_bridge_remove(&dsi->bridge);
> +	return 0;
> +}
> +
>  static void mtk_dsi_wait_for_idle(struct mtk_dsi *dsi)
>  {
>  	int ret;
> @@ -938,73 +1021,14 @@ static ssize_t mtk_dsi_host_transfer(struct mipi_dsi_host *host,
>  
>  static const struct mipi_dsi_host_ops mtk_dsi_ops = {
>  	.attach = mtk_dsi_host_attach,
> +	.detach = mtk_dsi_host_detach,
>  	.transfer = mtk_dsi_host_transfer,
>  };
>  
> -static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi)
> -{
> -	int ret;
> -
> -	ret = drm_simple_encoder_init(drm, &dsi->encoder,
> -				      DRM_MODE_ENCODER_DSI);
> -	if (ret) {
> -		DRM_ERROR("Failed to encoder init to drm\n");
> -		return ret;
> -	}
> -
> -	dsi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
> -
> -	ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL,
> -				DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> -	if (ret)
> -		goto err_cleanup_encoder;
> -
> -	dsi->connector = drm_bridge_connector_init(drm, &dsi->encoder);
> -	if (IS_ERR(dsi->connector)) {
> -		DRM_ERROR("Unable to create bridge connector\n");
> -		ret = PTR_ERR(dsi->connector);
> -		goto err_cleanup_encoder;
> -	}
> -	drm_connector_attach_encoder(dsi->connector, &dsi->encoder);
> -
> -	return 0;
> -
> -err_cleanup_encoder:
> -	drm_encoder_cleanup(&dsi->encoder);
> -	return ret;
> -}
> -
> -static int mtk_dsi_bind(struct device *dev, struct device *master, void *data)
> -{
> -	int ret;
> -	struct drm_device *drm = data;
> -	struct mtk_dsi *dsi = dev_get_drvdata(dev);
> -
> -	ret = mtk_dsi_encoder_init(drm, dsi);
> -	if (ret)
> -		return ret;
> -
> -	return device_reset_optional(dev);
> -}
> -
> -static void mtk_dsi_unbind(struct device *dev, struct device *master,
> -			   void *data)
> -{
> -	struct mtk_dsi *dsi = dev_get_drvdata(dev);
> -
> -	drm_encoder_cleanup(&dsi->encoder);
> -}
> -
> -static const struct component_ops mtk_dsi_component_ops = {
> -	.bind = mtk_dsi_bind,
> -	.unbind = mtk_dsi_unbind,
> -};
> -
>  static int mtk_dsi_probe(struct platform_device *pdev)
>  {
>  	struct mtk_dsi *dsi;
>  	struct device *dev = &pdev->dev;
> -	struct drm_panel *panel;
>  	struct resource *regs;
>  	int irq_num;
>  	int ret;
> @@ -1021,19 +1045,6 @@ static int mtk_dsi_probe(struct platform_device *pdev)
>  		return ret;
>  	}
>  
> -	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0,
> -					  &panel, &dsi->next_bridge);
> -	if (ret)
> -		goto err_unregister_host;
> -
> -	if (panel) {
> -		dsi->next_bridge = devm_drm_panel_bridge_add(dev, panel);
> -		if (IS_ERR(dsi->next_bridge)) {
> -			ret = PTR_ERR(dsi->next_bridge);
> -			goto err_unregister_host;
> -		}
> -	}
> -
>  	dsi->driver_data = of_device_get_match_data(dev);
>  
>  	dsi->engine_clk = devm_clk_get(dev, "engine");
> @@ -1098,14 +1109,6 @@ static int mtk_dsi_probe(struct platform_device *pdev)
>  	dsi->bridge.of_node = dev->of_node;
>  	dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
>  
> -	drm_bridge_add(&dsi->bridge);
> -
> -	ret = component_add(&pdev->dev, &mtk_dsi_component_ops);
> -	if (ret) {
> -		dev_err(&pdev->dev, "failed to add component: %d\n", ret);
> -		goto err_unregister_host;
> -	}
> -
>  	return 0;
>  
>  err_unregister_host:
> @@ -1118,8 +1121,6 @@ static int mtk_dsi_remove(struct platform_device *pdev)
>  	struct mtk_dsi *dsi = platform_get_drvdata(pdev);
>  
>  	mtk_output_dsi_disable(dsi);
> -	drm_bridge_remove(&dsi->bridge);
> -	component_del(&pdev->dev, &mtk_dsi_component_ops);
>  	mipi_dsi_host_unregister(&dsi->host);
>  
>  	return 0;
> -- 
> 2.33.1
> 
> 
> -- 
> To unsubscribe, send mail to kernel-unsubscribe@lists.collabora.co.uk.

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Re: [PATCH v4] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[Nícolas F. R. A. Prado]

Hi Angelo,

On Mon, Jan 31, 2022 at 09:55:20AM +0100, AngeloGioacchino Del Regno wrote:
> DRM bridge drivers are now attaching their DSI device at probe time,
> which requires us to register our DSI host in order to let the bridge
> to probe: this recently started producing an endless -EPROBE_DEFER
> loop on some machines that are using external bridges, like the
> parade-ps8640, found on the ACER Chromebook R13.
> 
> Now that the DSI hosts/devices probe sequence is documented, we can
> do adjustments to the mtk_dsi driver as to both fix now and make sure
> to avoid this situation in the future: for this, following what is
> documented in drm_bridge.c, move the mtk_dsi component_add() to the
> mtk_dsi_ops.attach callback and delete it in the detach callback;
> keeping in mind that we are registering a drm_bridge for our DSI,
> which is only used/attached if the DSI Host is bound, it wouldn't
> make sense to keep adding our bridge at probe time (as it would
> be useless to have it if mtk_dsi_ops.attach() fails!), so also move
> that one to the dsi host attach function (and remove it in detach).
> 
> Cc: <stable@vger.kernel.org> # 5.15.x
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
> Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>

Tested-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>

Thanks,
Nícolas

> 
> ---
>  drivers/gpu/drm/mediatek/mtk_dsi.c | 167 +++++++++++++++--------------
>  1 file changed, 84 insertions(+), 83 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index 5d90d2eb0019..bced4c7d668e 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -786,18 +786,101 @@ void mtk_dsi_ddp_stop(struct device *dev)
>  	mtk_dsi_poweroff(dsi);
>  }
>  
> +static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi)
> +{
> +	int ret;
> +
> +	ret = drm_simple_encoder_init(drm, &dsi->encoder,
> +				      DRM_MODE_ENCODER_DSI);
> +	if (ret) {
> +		DRM_ERROR("Failed to encoder init to drm\n");
> +		return ret;
> +	}
> +
> +	dsi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
> +
> +	ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL,
> +				DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> +	if (ret)
> +		goto err_cleanup_encoder;
> +
> +	dsi->connector = drm_bridge_connector_init(drm, &dsi->encoder);
> +	if (IS_ERR(dsi->connector)) {
> +		DRM_ERROR("Unable to create bridge connector\n");
> +		ret = PTR_ERR(dsi->connector);
> +		goto err_cleanup_encoder;
> +	}
> +	drm_connector_attach_encoder(dsi->connector, &dsi->encoder);
> +
> +	return 0;
> +
> +err_cleanup_encoder:
> +	drm_encoder_cleanup(&dsi->encoder);
> +	return ret;
> +}
> +
> +static int mtk_dsi_bind(struct device *dev, struct device *master, void *data)
> +{
> +	int ret;
> +	struct drm_device *drm = data;
> +	struct mtk_dsi *dsi = dev_get_drvdata(dev);
> +
> +	ret = mtk_dsi_encoder_init(drm, dsi);
> +	if (ret)
> +		return ret;
> +
> +	return device_reset_optional(dev);
> +}
> +
> +static void mtk_dsi_unbind(struct device *dev, struct device *master,
> +			   void *data)
> +{
> +	struct mtk_dsi *dsi = dev_get_drvdata(dev);
> +
> +	drm_encoder_cleanup(&dsi->encoder);
> +}
> +
> +static const struct component_ops mtk_dsi_component_ops = {
> +	.bind = mtk_dsi_bind,
> +	.unbind = mtk_dsi_unbind,
> +};
> +
>  static int mtk_dsi_host_attach(struct mipi_dsi_host *host,
>  			       struct mipi_dsi_device *device)
>  {
>  	struct mtk_dsi *dsi = host_to_dsi(host);
> +	struct device *dev = host->dev;
> +	int ret;
>  
>  	dsi->lanes = device->lanes;
>  	dsi->format = device->format;
>  	dsi->mode_flags = device->mode_flags;
> +	dsi->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0);
> +	if (IS_ERR(dsi->next_bridge))
> +		return PTR_ERR(dsi->next_bridge);
> +
> +	drm_bridge_add(&dsi->bridge);
> +
> +	ret = component_add(host->dev, &mtk_dsi_component_ops);
> +	if (ret) {
> +		DRM_ERROR("failed to add dsi_host component: %d\n", ret);
> +		drm_bridge_remove(&dsi->bridge);
> +		return ret;
> +	}
>  
>  	return 0;
>  }
>  
> +static int mtk_dsi_host_detach(struct mipi_dsi_host *host,
> +			       struct mipi_dsi_device *device)
> +{
> +	struct mtk_dsi *dsi = host_to_dsi(host);
> +
> +	component_del(host->dev, &mtk_dsi_component_ops);
> +	drm_bridge_remove(&dsi->bridge);
> +	return 0;
> +}
> +
>  static void mtk_dsi_wait_for_idle(struct mtk_dsi *dsi)
>  {
>  	int ret;
> @@ -938,73 +1021,14 @@ static ssize_t mtk_dsi_host_transfer(struct mipi_dsi_host *host,
>  
>  static const struct mipi_dsi_host_ops mtk_dsi_ops = {
>  	.attach = mtk_dsi_host_attach,
> +	.detach = mtk_dsi_host_detach,
>  	.transfer = mtk_dsi_host_transfer,
>  };
>  
> -static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi)
> -{
> -	int ret;
> -
> -	ret = drm_simple_encoder_init(drm, &dsi->encoder,
> -				      DRM_MODE_ENCODER_DSI);
> -	if (ret) {
> -		DRM_ERROR("Failed to encoder init to drm\n");
> -		return ret;
> -	}
> -
> -	dsi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
> -
> -	ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL,
> -				DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> -	if (ret)
> -		goto err_cleanup_encoder;
> -
> -	dsi->connector = drm_bridge_connector_init(drm, &dsi->encoder);
> -	if (IS_ERR(dsi->connector)) {
> -		DRM_ERROR("Unable to create bridge connector\n");
> -		ret = PTR_ERR(dsi->connector);
> -		goto err_cleanup_encoder;
> -	}
> -	drm_connector_attach_encoder(dsi->connector, &dsi->encoder);
> -
> -	return 0;
> -
> -err_cleanup_encoder:
> -	drm_encoder_cleanup(&dsi->encoder);
> -	return ret;
> -}
> -
> -static int mtk_dsi_bind(struct device *dev, struct device *master, void *data)
> -{
> -	int ret;
> -	struct drm_device *drm = data;
> -	struct mtk_dsi *dsi = dev_get_drvdata(dev);
> -
> -	ret = mtk_dsi_encoder_init(drm, dsi);
> -	if (ret)
> -		return ret;
> -
> -	return device_reset_optional(dev);
> -}
> -
> -static void mtk_dsi_unbind(struct device *dev, struct device *master,
> -			   void *data)
> -{
> -	struct mtk_dsi *dsi = dev_get_drvdata(dev);
> -
> -	drm_encoder_cleanup(&dsi->encoder);
> -}
> -
> -static const struct component_ops mtk_dsi_component_ops = {
> -	.bind = mtk_dsi_bind,
> -	.unbind = mtk_dsi_unbind,
> -};
> -
>  static int mtk_dsi_probe(struct platform_device *pdev)
>  {
>  	struct mtk_dsi *dsi;
>  	struct device *dev = &pdev->dev;
> -	struct drm_panel *panel;
>  	struct resource *regs;
>  	int irq_num;
>  	int ret;
> @@ -1021,19 +1045,6 @@ static int mtk_dsi_probe(struct platform_device *pdev)
>  		return ret;
>  	}
>  
> -	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0,
> -					  &panel, &dsi->next_bridge);
> -	if (ret)
> -		goto err_unregister_host;
> -
> -	if (panel) {
> -		dsi->next_bridge = devm_drm_panel_bridge_add(dev, panel);
> -		if (IS_ERR(dsi->next_bridge)) {
> -			ret = PTR_ERR(dsi->next_bridge);
> -			goto err_unregister_host;
> -		}
> -	}
> -
>  	dsi->driver_data = of_device_get_match_data(dev);
>  
>  	dsi->engine_clk = devm_clk_get(dev, "engine");
> @@ -1098,14 +1109,6 @@ static int mtk_dsi_probe(struct platform_device *pdev)
>  	dsi->bridge.of_node = dev->of_node;
>  	dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
>  
> -	drm_bridge_add(&dsi->bridge);
> -
> -	ret = component_add(&pdev->dev, &mtk_dsi_component_ops);
> -	if (ret) {
> -		dev_err(&pdev->dev, "failed to add component: %d\n", ret);
> -		goto err_unregister_host;
> -	}
> -
>  	return 0;
>  
>  err_unregister_host:
> @@ -1118,8 +1121,6 @@ static int mtk_dsi_remove(struct platform_device *pdev)
>  	struct mtk_dsi *dsi = platform_get_drvdata(pdev);
>  
>  	mtk_output_dsi_disable(dsi);
> -	drm_bridge_remove(&dsi->bridge);
> -	component_del(&pdev->dev, &mtk_dsi_component_ops);
>  	mipi_dsi_host_unregister(&dsi->host);
>  
>  	return 0;
> -- 
> 2.33.1
> 
> 
> -- 
> To unsubscribe, send mail to kernel-unsubscribe@lists.collabora.co.uk.

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Re: [PATCH v4] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[Chun-Kuang Hu]

 Hi, Angelo:

AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> 於
2022年1月31日 週一 下午4:55寫道：
>
> DRM bridge drivers are now attaching their DSI device at probe time,
> which requires us to register our DSI host in order to let the bridge
> to probe: this recently started producing an endless -EPROBE_DEFER
> loop on some machines that are using external bridges, like the
> parade-ps8640, found on the ACER Chromebook R13.
>
> Now that the DSI hosts/devices probe sequence is documented, we can
> do adjustments to the mtk_dsi driver as to both fix now and make sure
> to avoid this situation in the future: for this, following what is
> documented in drm_bridge.c, move the mtk_dsi component_add() to the
> mtk_dsi_ops.attach callback and delete it in the detach callback;
> keeping in mind that we are registering a drm_bridge for our DSI,
> which is only used/attached if the DSI Host is bound, it wouldn't
> make sense to keep adding our bridge at probe time (as it would
> be useless to have it if mtk_dsi_ops.attach() fails!), so also move
> that one to the dsi host attach function (and remove it in detach).

Applied to mediatek-drm-fixes[1], thanks.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/chunkuang.hu/linux.git/log/?h=mediatek-drm-fixes

Regards,
Chun-Kuang.

>
> Cc: <stable@vger.kernel.org> # 5.15.x
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
> Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
>
> ---
>  drivers/gpu/drm/mediatek/mtk_dsi.c | 167 +++++++++++++++--------------
>  1 file changed, 84 insertions(+), 83 deletions(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index 5d90d2eb0019..bced4c7d668e 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -786,18 +786,101 @@ void mtk_dsi_ddp_stop(struct device *dev)
>         mtk_dsi_poweroff(dsi);
>  }
>
> +static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi)
> +{
> +       int ret;
> +
> +       ret = drm_simple_encoder_init(drm, &dsi->encoder,
> +                                     DRM_MODE_ENCODER_DSI);
> +       if (ret) {
> +               DRM_ERROR("Failed to encoder init to drm\n");
> +               return ret;
> +       }
> +
> +       dsi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
> +
> +       ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL,
> +                               DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> +       if (ret)
> +               goto err_cleanup_encoder;
> +
> +       dsi->connector = drm_bridge_connector_init(drm, &dsi->encoder);
> +       if (IS_ERR(dsi->connector)) {
> +               DRM_ERROR("Unable to create bridge connector\n");
> +               ret = PTR_ERR(dsi->connector);
> +               goto err_cleanup_encoder;
> +       }
> +       drm_connector_attach_encoder(dsi->connector, &dsi->encoder);
> +
> +       return 0;
> +
> +err_cleanup_encoder:
> +       drm_encoder_cleanup(&dsi->encoder);
> +       return ret;
> +}
> +
> +static int mtk_dsi_bind(struct device *dev, struct device *master, void *data)
> +{
> +       int ret;
> +       struct drm_device *drm = data;
> +       struct mtk_dsi *dsi = dev_get_drvdata(dev);
> +
> +       ret = mtk_dsi_encoder_init(drm, dsi);
> +       if (ret)
> +               return ret;
> +
> +       return device_reset_optional(dev);
> +}
> +
> +static void mtk_dsi_unbind(struct device *dev, struct device *master,
> +                          void *data)
> +{
> +       struct mtk_dsi *dsi = dev_get_drvdata(dev);
> +
> +       drm_encoder_cleanup(&dsi->encoder);
> +}
> +
> +static const struct component_ops mtk_dsi_component_ops = {
> +       .bind = mtk_dsi_bind,
> +       .unbind = mtk_dsi_unbind,
> +};
> +
>  static int mtk_dsi_host_attach(struct mipi_dsi_host *host,
>                                struct mipi_dsi_device *device)
>  {
>         struct mtk_dsi *dsi = host_to_dsi(host);
> +       struct device *dev = host->dev;
> +       int ret;
>
>         dsi->lanes = device->lanes;
>         dsi->format = device->format;
>         dsi->mode_flags = device->mode_flags;
> +       dsi->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0);
> +       if (IS_ERR(dsi->next_bridge))
> +               return PTR_ERR(dsi->next_bridge);
> +
> +       drm_bridge_add(&dsi->bridge);
> +
> +       ret = component_add(host->dev, &mtk_dsi_component_ops);
> +       if (ret) {
> +               DRM_ERROR("failed to add dsi_host component: %d\n", ret);
> +               drm_bridge_remove(&dsi->bridge);
> +               return ret;
> +       }
>
>         return 0;
>  }
>
> +static int mtk_dsi_host_detach(struct mipi_dsi_host *host,
> +                              struct mipi_dsi_device *device)
> +{
> +       struct mtk_dsi *dsi = host_to_dsi(host);
> +
> +       component_del(host->dev, &mtk_dsi_component_ops);
> +       drm_bridge_remove(&dsi->bridge);
> +       return 0;
> +}
> +
>  static void mtk_dsi_wait_for_idle(struct mtk_dsi *dsi)
>  {
>         int ret;
> @@ -938,73 +1021,14 @@ static ssize_t mtk_dsi_host_transfer(struct mipi_dsi_host *host,
>
>  static const struct mipi_dsi_host_ops mtk_dsi_ops = {
>         .attach = mtk_dsi_host_attach,
> +       .detach = mtk_dsi_host_detach,
>         .transfer = mtk_dsi_host_transfer,
>  };
>
> -static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi)
> -{
> -       int ret;
> -
> -       ret = drm_simple_encoder_init(drm, &dsi->encoder,
> -                                     DRM_MODE_ENCODER_DSI);
> -       if (ret) {
> -               DRM_ERROR("Failed to encoder init to drm\n");
> -               return ret;
> -       }
> -
> -       dsi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
> -
> -       ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL,
> -                               DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> -       if (ret)
> -               goto err_cleanup_encoder;
> -
> -       dsi->connector = drm_bridge_connector_init(drm, &dsi->encoder);
> -       if (IS_ERR(dsi->connector)) {
> -               DRM_ERROR("Unable to create bridge connector\n");
> -               ret = PTR_ERR(dsi->connector);
> -               goto err_cleanup_encoder;
> -       }
> -       drm_connector_attach_encoder(dsi->connector, &dsi->encoder);
> -
> -       return 0;
> -
> -err_cleanup_encoder:
> -       drm_encoder_cleanup(&dsi->encoder);
> -       return ret;
> -}
> -
> -static int mtk_dsi_bind(struct device *dev, struct device *master, void *data)
> -{
> -       int ret;
> -       struct drm_device *drm = data;
> -       struct mtk_dsi *dsi = dev_get_drvdata(dev);
> -
> -       ret = mtk_dsi_encoder_init(drm, dsi);
> -       if (ret)
> -               return ret;
> -
> -       return device_reset_optional(dev);
> -}
> -
> -static void mtk_dsi_unbind(struct device *dev, struct device *master,
> -                          void *data)
> -{
> -       struct mtk_dsi *dsi = dev_get_drvdata(dev);
> -
> -       drm_encoder_cleanup(&dsi->encoder);
> -}
> -
> -static const struct component_ops mtk_dsi_component_ops = {
> -       .bind = mtk_dsi_bind,
> -       .unbind = mtk_dsi_unbind,
> -};
> -
>  static int mtk_dsi_probe(struct platform_device *pdev)
>  {
>         struct mtk_dsi *dsi;
>         struct device *dev = &pdev->dev;
> -       struct drm_panel *panel;
>         struct resource *regs;
>         int irq_num;
>         int ret;
> @@ -1021,19 +1045,6 @@ static int mtk_dsi_probe(struct platform_device *pdev)
>                 return ret;
>         }
>
> -       ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0,
> -                                         &panel, &dsi->next_bridge);
> -       if (ret)
> -               goto err_unregister_host;
> -
> -       if (panel) {
> -               dsi->next_bridge = devm_drm_panel_bridge_add(dev, panel);
> -               if (IS_ERR(dsi->next_bridge)) {
> -                       ret = PTR_ERR(dsi->next_bridge);
> -                       goto err_unregister_host;
> -               }
> -       }
> -
>         dsi->driver_data = of_device_get_match_data(dev);
>
>         dsi->engine_clk = devm_clk_get(dev, "engine");
> @@ -1098,14 +1109,6 @@ static int mtk_dsi_probe(struct platform_device *pdev)
>         dsi->bridge.of_node = dev->of_node;
>         dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
>
> -       drm_bridge_add(&dsi->bridge);
> -
> -       ret = component_add(&pdev->dev, &mtk_dsi_component_ops);
> -       if (ret) {
> -               dev_err(&pdev->dev, "failed to add component: %d\n", ret);
> -               goto err_unregister_host;
> -       }
> -
>         return 0;
>
>  err_unregister_host:
> @@ -1118,8 +1121,6 @@ static int mtk_dsi_remove(struct platform_device *pdev)
>         struct mtk_dsi *dsi = platform_get_drvdata(pdev);
>
>         mtk_output_dsi_disable(dsi);
> -       drm_bridge_remove(&dsi->bridge);
> -       component_del(&pdev->dev, &mtk_dsi_component_ops);
>         mipi_dsi_host_unregister(&dsi->host);
>
>         return 0;
> --
> 2.33.1
>

Re: [PATCH v4] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[Chun-Kuang Hu]

 Hi, Angelo:

AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> 於
2022年1月31日 週一 下午4:55寫道：
>
> DRM bridge drivers are now attaching their DSI device at probe time,
> which requires us to register our DSI host in order to let the bridge
> to probe: this recently started producing an endless -EPROBE_DEFER
> loop on some machines that are using external bridges, like the
> parade-ps8640, found on the ACER Chromebook R13.
>
> Now that the DSI hosts/devices probe sequence is documented, we can
> do adjustments to the mtk_dsi driver as to both fix now and make sure
> to avoid this situation in the future: for this, following what is
> documented in drm_bridge.c, move the mtk_dsi component_add() to the
> mtk_dsi_ops.attach callback and delete it in the detach callback;
> keeping in mind that we are registering a drm_bridge for our DSI,
> which is only used/attached if the DSI Host is bound, it wouldn't
> make sense to keep adding our bridge at probe time (as it would
> be useless to have it if mtk_dsi_ops.attach() fails!), so also move
> that one to the dsi host attach function (and remove it in detach).

Applied to mediatek-drm-fixes[1], thanks.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/chunkuang.hu/linux.git/log/?h=mediatek-drm-fixes

Regards,
Chun-Kuang.

>
> Cc: <stable@vger.kernel.org> # 5.15.x
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
> Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
>
> ---
>  drivers/gpu/drm/mediatek/mtk_dsi.c | 167 +++++++++++++++--------------
>  1 file changed, 84 insertions(+), 83 deletions(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index 5d90d2eb0019..bced4c7d668e 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -786,18 +786,101 @@ void mtk_dsi_ddp_stop(struct device *dev)
>         mtk_dsi_poweroff(dsi);
>  }
>
> +static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi)
> +{
> +       int ret;
> +
> +       ret = drm_simple_encoder_init(drm, &dsi->encoder,
> +                                     DRM_MODE_ENCODER_DSI);
> +       if (ret) {
> +               DRM_ERROR("Failed to encoder init to drm\n");
> +               return ret;
> +       }
> +
> +       dsi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
> +
> +       ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL,
> +                               DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> +       if (ret)
> +               goto err_cleanup_encoder;
> +
> +       dsi->connector = drm_bridge_connector_init(drm, &dsi->encoder);
> +       if (IS_ERR(dsi->connector)) {
> +               DRM_ERROR("Unable to create bridge connector\n");
> +               ret = PTR_ERR(dsi->connector);
> +               goto err_cleanup_encoder;
> +       }
> +       drm_connector_attach_encoder(dsi->connector, &dsi->encoder);
> +
> +       return 0;
> +
> +err_cleanup_encoder:
> +       drm_encoder_cleanup(&dsi->encoder);
> +       return ret;
> +}
> +
> +static int mtk_dsi_bind(struct device *dev, struct device *master, void *data)
> +{
> +       int ret;
> +       struct drm_device *drm = data;
> +       struct mtk_dsi *dsi = dev_get_drvdata(dev);
> +
> +       ret = mtk_dsi_encoder_init(drm, dsi);
> +       if (ret)
> +               return ret;
> +
> +       return device_reset_optional(dev);
> +}
> +
> +static void mtk_dsi_unbind(struct device *dev, struct device *master,
> +                          void *data)
> +{
> +       struct mtk_dsi *dsi = dev_get_drvdata(dev);
> +
> +       drm_encoder_cleanup(&dsi->encoder);
> +}
> +
> +static const struct component_ops mtk_dsi_component_ops = {
> +       .bind = mtk_dsi_bind,
> +       .unbind = mtk_dsi_unbind,
> +};
> +
>  static int mtk_dsi_host_attach(struct mipi_dsi_host *host,
>                                struct mipi_dsi_device *device)
>  {
>         struct mtk_dsi *dsi = host_to_dsi(host);
> +       struct device *dev = host->dev;
> +       int ret;
>
>         dsi->lanes = device->lanes;
>         dsi->format = device->format;
>         dsi->mode_flags = device->mode_flags;
> +       dsi->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0);
> +       if (IS_ERR(dsi->next_bridge))
> +               return PTR_ERR(dsi->next_bridge);
> +
> +       drm_bridge_add(&dsi->bridge);
> +
> +       ret = component_add(host->dev, &mtk_dsi_component_ops);
> +       if (ret) {
> +               DRM_ERROR("failed to add dsi_host component: %d\n", ret);
> +               drm_bridge_remove(&dsi->bridge);
> +               return ret;
> +       }
>
>         return 0;
>  }
>
> +static int mtk_dsi_host_detach(struct mipi_dsi_host *host,
> +                              struct mipi_dsi_device *device)
> +{
> +       struct mtk_dsi *dsi = host_to_dsi(host);
> +
> +       component_del(host->dev, &mtk_dsi_component_ops);
> +       drm_bridge_remove(&dsi->bridge);
> +       return 0;
> +}
> +
>  static void mtk_dsi_wait_for_idle(struct mtk_dsi *dsi)
>  {
>         int ret;
> @@ -938,73 +1021,14 @@ static ssize_t mtk_dsi_host_transfer(struct mipi_dsi_host *host,
>
>  static const struct mipi_dsi_host_ops mtk_dsi_ops = {
>         .attach = mtk_dsi_host_attach,
> +       .detach = mtk_dsi_host_detach,
>         .transfer = mtk_dsi_host_transfer,
>  };
>
> -static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi)
> -{
> -       int ret;
> -
> -       ret = drm_simple_encoder_init(drm, &dsi->encoder,
> -                                     DRM_MODE_ENCODER_DSI);
> -       if (ret) {
> -               DRM_ERROR("Failed to encoder init to drm\n");
> -               return ret;
> -       }
> -
> -       dsi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
> -
> -       ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL,
> -                               DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> -       if (ret)
> -               goto err_cleanup_encoder;
> -
> -       dsi->connector = drm_bridge_connector_init(drm, &dsi->encoder);
> -       if (IS_ERR(dsi->connector)) {
> -               DRM_ERROR("Unable to create bridge connector\n");
> -               ret = PTR_ERR(dsi->connector);
> -               goto err_cleanup_encoder;
> -       }
> -       drm_connector_attach_encoder(dsi->connector, &dsi->encoder);
> -
> -       return 0;
> -
> -err_cleanup_encoder:
> -       drm_encoder_cleanup(&dsi->encoder);
> -       return ret;
> -}
> -
> -static int mtk_dsi_bind(struct device *dev, struct device *master, void *data)
> -{
> -       int ret;
> -       struct drm_device *drm = data;
> -       struct mtk_dsi *dsi = dev_get_drvdata(dev);
> -
> -       ret = mtk_dsi_encoder_init(drm, dsi);
> -       if (ret)
> -               return ret;
> -
> -       return device_reset_optional(dev);
> -}
> -
> -static void mtk_dsi_unbind(struct device *dev, struct device *master,
> -                          void *data)
> -{
> -       struct mtk_dsi *dsi = dev_get_drvdata(dev);
> -
> -       drm_encoder_cleanup(&dsi->encoder);
> -}
> -
> -static const struct component_ops mtk_dsi_component_ops = {
> -       .bind = mtk_dsi_bind,
> -       .unbind = mtk_dsi_unbind,
> -};
> -
>  static int mtk_dsi_probe(struct platform_device *pdev)
>  {
>         struct mtk_dsi *dsi;
>         struct device *dev = &pdev->dev;
> -       struct drm_panel *panel;
>         struct resource *regs;
>         int irq_num;
>         int ret;
> @@ -1021,19 +1045,6 @@ static int mtk_dsi_probe(struct platform_device *pdev)
>                 return ret;
>         }
>
> -       ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0,
> -                                         &panel, &dsi->next_bridge);
> -       if (ret)
> -               goto err_unregister_host;
> -
> -       if (panel) {
> -               dsi->next_bridge = devm_drm_panel_bridge_add(dev, panel);
> -               if (IS_ERR(dsi->next_bridge)) {
> -                       ret = PTR_ERR(dsi->next_bridge);
> -                       goto err_unregister_host;
> -               }
> -       }
> -
>         dsi->driver_data = of_device_get_match_data(dev);
>
>         dsi->engine_clk = devm_clk_get(dev, "engine");
> @@ -1098,14 +1109,6 @@ static int mtk_dsi_probe(struct platform_device *pdev)
>         dsi->bridge.of_node = dev->of_node;
>         dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
>
> -       drm_bridge_add(&dsi->bridge);
> -
> -       ret = component_add(&pdev->dev, &mtk_dsi_component_ops);
> -       if (ret) {
> -               dev_err(&pdev->dev, "failed to add component: %d\n", ret);
> -               goto err_unregister_host;
> -       }
> -
>         return 0;
>
>  err_unregister_host:
> @@ -1118,8 +1121,6 @@ static int mtk_dsi_remove(struct platform_device *pdev)
>         struct mtk_dsi *dsi = platform_get_drvdata(pdev);
>
>         mtk_output_dsi_disable(dsi);
> -       drm_bridge_remove(&dsi->bridge);
> -       component_del(&pdev->dev, &mtk_dsi_component_ops);
>         mipi_dsi_host_unregister(&dsi->host);
>
>         return 0;
> --
> 2.33.1
>

Re: [PATCH v4] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[Chun-Kuang Hu]

 Hi, Angelo:

AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> 於
2022年1月31日 週一 下午4:55寫道：
>
> DRM bridge drivers are now attaching their DSI device at probe time,
> which requires us to register our DSI host in order to let the bridge
> to probe: this recently started producing an endless -EPROBE_DEFER
> loop on some machines that are using external bridges, like the
> parade-ps8640, found on the ACER Chromebook R13.
>
> Now that the DSI hosts/devices probe sequence is documented, we can
> do adjustments to the mtk_dsi driver as to both fix now and make sure
> to avoid this situation in the future: for this, following what is
> documented in drm_bridge.c, move the mtk_dsi component_add() to the
> mtk_dsi_ops.attach callback and delete it in the detach callback;
> keeping in mind that we are registering a drm_bridge for our DSI,
> which is only used/attached if the DSI Host is bound, it wouldn't
> make sense to keep adding our bridge at probe time (as it would
> be useless to have it if mtk_dsi_ops.attach() fails!), so also move
> that one to the dsi host attach function (and remove it in detach).

Applied to mediatek-drm-fixes[1], thanks.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/chunkuang.hu/linux.git/log/?h=mediatek-drm-fixes

Regards,
Chun-Kuang.

>
> Cc: <stable@vger.kernel.org> # 5.15.x
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
> Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
>
> ---
>  drivers/gpu/drm/mediatek/mtk_dsi.c | 167 +++++++++++++++--------------
>  1 file changed, 84 insertions(+), 83 deletions(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index 5d90d2eb0019..bced4c7d668e 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -786,18 +786,101 @@ void mtk_dsi_ddp_stop(struct device *dev)
>         mtk_dsi_poweroff(dsi);
>  }
>
> +static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi)
> +{
> +       int ret;
> +
> +       ret = drm_simple_encoder_init(drm, &dsi->encoder,
> +                                     DRM_MODE_ENCODER_DSI);
> +       if (ret) {
> +               DRM_ERROR("Failed to encoder init to drm\n");
> +               return ret;
> +       }
> +
> +       dsi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
> +
> +       ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL,
> +                               DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> +       if (ret)
> +               goto err_cleanup_encoder;
> +
> +       dsi->connector = drm_bridge_connector_init(drm, &dsi->encoder);
> +       if (IS_ERR(dsi->connector)) {
> +               DRM_ERROR("Unable to create bridge connector\n");
> +               ret = PTR_ERR(dsi->connector);
> +               goto err_cleanup_encoder;
> +       }
> +       drm_connector_attach_encoder(dsi->connector, &dsi->encoder);
> +
> +       return 0;
> +
> +err_cleanup_encoder:
> +       drm_encoder_cleanup(&dsi->encoder);
> +       return ret;
> +}
> +
> +static int mtk_dsi_bind(struct device *dev, struct device *master, void *data)
> +{
> +       int ret;
> +       struct drm_device *drm = data;
> +       struct mtk_dsi *dsi = dev_get_drvdata(dev);
> +
> +       ret = mtk_dsi_encoder_init(drm, dsi);
> +       if (ret)
> +               return ret;
> +
> +       return device_reset_optional(dev);
> +}
> +
> +static void mtk_dsi_unbind(struct device *dev, struct device *master,
> +                          void *data)
> +{
> +       struct mtk_dsi *dsi = dev_get_drvdata(dev);
> +
> +       drm_encoder_cleanup(&dsi->encoder);
> +}
> +
> +static const struct component_ops mtk_dsi_component_ops = {
> +       .bind = mtk_dsi_bind,
> +       .unbind = mtk_dsi_unbind,
> +};
> +
>  static int mtk_dsi_host_attach(struct mipi_dsi_host *host,
>                                struct mipi_dsi_device *device)
>  {
>         struct mtk_dsi *dsi = host_to_dsi(host);
> +       struct device *dev = host->dev;
> +       int ret;
>
>         dsi->lanes = device->lanes;
>         dsi->format = device->format;
>         dsi->mode_flags = device->mode_flags;
> +       dsi->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0);
> +       if (IS_ERR(dsi->next_bridge))
> +               return PTR_ERR(dsi->next_bridge);
> +
> +       drm_bridge_add(&dsi->bridge);
> +
> +       ret = component_add(host->dev, &mtk_dsi_component_ops);
> +       if (ret) {
> +               DRM_ERROR("failed to add dsi_host component: %d\n", ret);
> +               drm_bridge_remove(&dsi->bridge);
> +               return ret;
> +       }
>
>         return 0;
>  }
>
> +static int mtk_dsi_host_detach(struct mipi_dsi_host *host,
> +                              struct mipi_dsi_device *device)
> +{
> +       struct mtk_dsi *dsi = host_to_dsi(host);
> +
> +       component_del(host->dev, &mtk_dsi_component_ops);
> +       drm_bridge_remove(&dsi->bridge);
> +       return 0;
> +}
> +
>  static void mtk_dsi_wait_for_idle(struct mtk_dsi *dsi)
>  {
>         int ret;
> @@ -938,73 +1021,14 @@ static ssize_t mtk_dsi_host_transfer(struct mipi_dsi_host *host,
>
>  static const struct mipi_dsi_host_ops mtk_dsi_ops = {
>         .attach = mtk_dsi_host_attach,
> +       .detach = mtk_dsi_host_detach,
>         .transfer = mtk_dsi_host_transfer,
>  };
>
> -static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi)
> -{
> -       int ret;
> -
> -       ret = drm_simple_encoder_init(drm, &dsi->encoder,
> -                                     DRM_MODE_ENCODER_DSI);
> -       if (ret) {
> -               DRM_ERROR("Failed to encoder init to drm\n");
> -               return ret;
> -       }
> -
> -       dsi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
> -
> -       ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL,
> -                               DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> -       if (ret)
> -               goto err_cleanup_encoder;
> -
> -       dsi->connector = drm_bridge_connector_init(drm, &dsi->encoder);
> -       if (IS_ERR(dsi->connector)) {
> -               DRM_ERROR("Unable to create bridge connector\n");
> -               ret = PTR_ERR(dsi->connector);
> -               goto err_cleanup_encoder;
> -       }
> -       drm_connector_attach_encoder(dsi->connector, &dsi->encoder);
> -
> -       return 0;
> -
> -err_cleanup_encoder:
> -       drm_encoder_cleanup(&dsi->encoder);
> -       return ret;
> -}
> -
> -static int mtk_dsi_bind(struct device *dev, struct device *master, void *data)
> -{
> -       int ret;
> -       struct drm_device *drm = data;
> -       struct mtk_dsi *dsi = dev_get_drvdata(dev);
> -
> -       ret = mtk_dsi_encoder_init(drm, dsi);
> -       if (ret)
> -               return ret;
> -
> -       return device_reset_optional(dev);
> -}
> -
> -static void mtk_dsi_unbind(struct device *dev, struct device *master,
> -                          void *data)
> -{
> -       struct mtk_dsi *dsi = dev_get_drvdata(dev);
> -
> -       drm_encoder_cleanup(&dsi->encoder);
> -}
> -
> -static const struct component_ops mtk_dsi_component_ops = {
> -       .bind = mtk_dsi_bind,
> -       .unbind = mtk_dsi_unbind,
> -};
> -
>  static int mtk_dsi_probe(struct platform_device *pdev)
>  {
>         struct mtk_dsi *dsi;
>         struct device *dev = &pdev->dev;
> -       struct drm_panel *panel;
>         struct resource *regs;
>         int irq_num;
>         int ret;
> @@ -1021,19 +1045,6 @@ static int mtk_dsi_probe(struct platform_device *pdev)
>                 return ret;
>         }
>
> -       ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0,
> -                                         &panel, &dsi->next_bridge);
> -       if (ret)
> -               goto err_unregister_host;
> -
> -       if (panel) {
> -               dsi->next_bridge = devm_drm_panel_bridge_add(dev, panel);
> -               if (IS_ERR(dsi->next_bridge)) {
> -                       ret = PTR_ERR(dsi->next_bridge);
> -                       goto err_unregister_host;
> -               }
> -       }
> -
>         dsi->driver_data = of_device_get_match_data(dev);
>
>         dsi->engine_clk = devm_clk_get(dev, "engine");
> @@ -1098,14 +1109,6 @@ static int mtk_dsi_probe(struct platform_device *pdev)
>         dsi->bridge.of_node = dev->of_node;
>         dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
>
> -       drm_bridge_add(&dsi->bridge);
> -
> -       ret = component_add(&pdev->dev, &mtk_dsi_component_ops);
> -       if (ret) {
> -               dev_err(&pdev->dev, "failed to add component: %d\n", ret);
> -               goto err_unregister_host;
> -       }
> -
>         return 0;
>
>  err_unregister_host:
> @@ -1118,8 +1121,6 @@ static int mtk_dsi_remove(struct platform_device *pdev)
>         struct mtk_dsi *dsi = platform_get_drvdata(pdev);
>
>         mtk_output_dsi_disable(dsi);
> -       drm_bridge_remove(&dsi->bridge);
> -       component_del(&pdev->dev, &mtk_dsi_component_ops);
>         mipi_dsi_host_unregister(&dsi->host);
>
>         return 0;
> --
> 2.33.1
>

_______________________________________________
Linux-mediatek mailing list
Linux-mediatek@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-mediatek

Re: [PATCH v4] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[Chun-Kuang Hu]

 Hi, Angelo:

AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> 於
2022年1月31日 週一 下午4:55寫道：
>
> DRM bridge drivers are now attaching their DSI device at probe time,
> which requires us to register our DSI host in order to let the bridge
> to probe: this recently started producing an endless -EPROBE_DEFER
> loop on some machines that are using external bridges, like the
> parade-ps8640, found on the ACER Chromebook R13.
>
> Now that the DSI hosts/devices probe sequence is documented, we can
> do adjustments to the mtk_dsi driver as to both fix now and make sure
> to avoid this situation in the future: for this, following what is
> documented in drm_bridge.c, move the mtk_dsi component_add() to the
> mtk_dsi_ops.attach callback and delete it in the detach callback;
> keeping in mind that we are registering a drm_bridge for our DSI,
> which is only used/attached if the DSI Host is bound, it wouldn't
> make sense to keep adding our bridge at probe time (as it would
> be useless to have it if mtk_dsi_ops.attach() fails!), so also move
> that one to the dsi host attach function (and remove it in detach).

Applied to mediatek-drm-fixes[1], thanks.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/chunkuang.hu/linux.git/log/?h=mediatek-drm-fixes

Regards,
Chun-Kuang.

>
> Cc: <stable@vger.kernel.org> # 5.15.x
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
> Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
>
> ---
>  drivers/gpu/drm/mediatek/mtk_dsi.c | 167 +++++++++++++++--------------
>  1 file changed, 84 insertions(+), 83 deletions(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index 5d90d2eb0019..bced4c7d668e 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -786,18 +786,101 @@ void mtk_dsi_ddp_stop(struct device *dev)
>         mtk_dsi_poweroff(dsi);
>  }
>
> +static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi)
> +{
> +       int ret;
> +
> +       ret = drm_simple_encoder_init(drm, &dsi->encoder,
> +                                     DRM_MODE_ENCODER_DSI);
> +       if (ret) {
> +               DRM_ERROR("Failed to encoder init to drm\n");
> +               return ret;
> +       }
> +
> +       dsi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
> +
> +       ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL,
> +                               DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> +       if (ret)
> +               goto err_cleanup_encoder;
> +
> +       dsi->connector = drm_bridge_connector_init(drm, &dsi->encoder);
> +       if (IS_ERR(dsi->connector)) {
> +               DRM_ERROR("Unable to create bridge connector\n");
> +               ret = PTR_ERR(dsi->connector);
> +               goto err_cleanup_encoder;
> +       }
> +       drm_connector_attach_encoder(dsi->connector, &dsi->encoder);
> +
> +       return 0;
> +
> +err_cleanup_encoder:
> +       drm_encoder_cleanup(&dsi->encoder);
> +       return ret;
> +}
> +
> +static int mtk_dsi_bind(struct device *dev, struct device *master, void *data)
> +{
> +       int ret;
> +       struct drm_device *drm = data;
> +       struct mtk_dsi *dsi = dev_get_drvdata(dev);
> +
> +       ret = mtk_dsi_encoder_init(drm, dsi);
> +       if (ret)
> +               return ret;
> +
> +       return device_reset_optional(dev);
> +}
> +
> +static void mtk_dsi_unbind(struct device *dev, struct device *master,
> +                          void *data)
> +{
> +       struct mtk_dsi *dsi = dev_get_drvdata(dev);
> +
> +       drm_encoder_cleanup(&dsi->encoder);
> +}
> +
> +static const struct component_ops mtk_dsi_component_ops = {
> +       .bind = mtk_dsi_bind,
> +       .unbind = mtk_dsi_unbind,
> +};
> +
>  static int mtk_dsi_host_attach(struct mipi_dsi_host *host,
>                                struct mipi_dsi_device *device)
>  {
>         struct mtk_dsi *dsi = host_to_dsi(host);
> +       struct device *dev = host->dev;
> +       int ret;
>
>         dsi->lanes = device->lanes;
>         dsi->format = device->format;
>         dsi->mode_flags = device->mode_flags;
> +       dsi->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, 0);
> +       if (IS_ERR(dsi->next_bridge))
> +               return PTR_ERR(dsi->next_bridge);
> +
> +       drm_bridge_add(&dsi->bridge);
> +
> +       ret = component_add(host->dev, &mtk_dsi_component_ops);
> +       if (ret) {
> +               DRM_ERROR("failed to add dsi_host component: %d\n", ret);
> +               drm_bridge_remove(&dsi->bridge);
> +               return ret;
> +       }
>
>         return 0;
>  }
>
> +static int mtk_dsi_host_detach(struct mipi_dsi_host *host,
> +                              struct mipi_dsi_device *device)
> +{
> +       struct mtk_dsi *dsi = host_to_dsi(host);
> +
> +       component_del(host->dev, &mtk_dsi_component_ops);
> +       drm_bridge_remove(&dsi->bridge);
> +       return 0;
> +}
> +
>  static void mtk_dsi_wait_for_idle(struct mtk_dsi *dsi)
>  {
>         int ret;
> @@ -938,73 +1021,14 @@ static ssize_t mtk_dsi_host_transfer(struct mipi_dsi_host *host,
>
>  static const struct mipi_dsi_host_ops mtk_dsi_ops = {
>         .attach = mtk_dsi_host_attach,
> +       .detach = mtk_dsi_host_detach,
>         .transfer = mtk_dsi_host_transfer,
>  };
>
> -static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi)
> -{
> -       int ret;
> -
> -       ret = drm_simple_encoder_init(drm, &dsi->encoder,
> -                                     DRM_MODE_ENCODER_DSI);
> -       if (ret) {
> -               DRM_ERROR("Failed to encoder init to drm\n");
> -               return ret;
> -       }
> -
> -       dsi->encoder.possible_crtcs = mtk_drm_find_possible_crtc_by_comp(drm, dsi->host.dev);
> -
> -       ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL,
> -                               DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> -       if (ret)
> -               goto err_cleanup_encoder;
> -
> -       dsi->connector = drm_bridge_connector_init(drm, &dsi->encoder);
> -       if (IS_ERR(dsi->connector)) {
> -               DRM_ERROR("Unable to create bridge connector\n");
> -               ret = PTR_ERR(dsi->connector);
> -               goto err_cleanup_encoder;
> -       }
> -       drm_connector_attach_encoder(dsi->connector, &dsi->encoder);
> -
> -       return 0;
> -
> -err_cleanup_encoder:
> -       drm_encoder_cleanup(&dsi->encoder);
> -       return ret;
> -}
> -
> -static int mtk_dsi_bind(struct device *dev, struct device *master, void *data)
> -{
> -       int ret;
> -       struct drm_device *drm = data;
> -       struct mtk_dsi *dsi = dev_get_drvdata(dev);
> -
> -       ret = mtk_dsi_encoder_init(drm, dsi);
> -       if (ret)
> -               return ret;
> -
> -       return device_reset_optional(dev);
> -}
> -
> -static void mtk_dsi_unbind(struct device *dev, struct device *master,
> -                          void *data)
> -{
> -       struct mtk_dsi *dsi = dev_get_drvdata(dev);
> -
> -       drm_encoder_cleanup(&dsi->encoder);
> -}
> -
> -static const struct component_ops mtk_dsi_component_ops = {
> -       .bind = mtk_dsi_bind,
> -       .unbind = mtk_dsi_unbind,
> -};
> -
>  static int mtk_dsi_probe(struct platform_device *pdev)
>  {
>         struct mtk_dsi *dsi;
>         struct device *dev = &pdev->dev;
> -       struct drm_panel *panel;
>         struct resource *regs;
>         int irq_num;
>         int ret;
> @@ -1021,19 +1045,6 @@ static int mtk_dsi_probe(struct platform_device *pdev)
>                 return ret;
>         }
>
> -       ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0,
> -                                         &panel, &dsi->next_bridge);
> -       if (ret)
> -               goto err_unregister_host;
> -
> -       if (panel) {
> -               dsi->next_bridge = devm_drm_panel_bridge_add(dev, panel);
> -               if (IS_ERR(dsi->next_bridge)) {
> -                       ret = PTR_ERR(dsi->next_bridge);
> -                       goto err_unregister_host;
> -               }
> -       }
> -
>         dsi->driver_data = of_device_get_match_data(dev);
>
>         dsi->engine_clk = devm_clk_get(dev, "engine");
> @@ -1098,14 +1109,6 @@ static int mtk_dsi_probe(struct platform_device *pdev)
>         dsi->bridge.of_node = dev->of_node;
>         dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
>
> -       drm_bridge_add(&dsi->bridge);
> -
> -       ret = component_add(&pdev->dev, &mtk_dsi_component_ops);
> -       if (ret) {
> -               dev_err(&pdev->dev, "failed to add component: %d\n", ret);
> -               goto err_unregister_host;
> -       }
> -
>         return 0;
>
>  err_unregister_host:
> @@ -1118,8 +1121,6 @@ static int mtk_dsi_remove(struct platform_device *pdev)
>         struct mtk_dsi *dsi = platform_get_drvdata(pdev);
>
>         mtk_output_dsi_disable(dsi);
> -       drm_bridge_remove(&dsi->bridge);
> -       component_del(&pdev->dev, &mtk_dsi_component_ops);
>         mipi_dsi_host_unregister(&dsi->host);
>
>         return 0;
> --
> 2.33.1
>

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