[PATCH v2] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[PATCH v2] 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).

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.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 v2] 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).

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.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 v2] 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).

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.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 v2] 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).

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.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 v2] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[CK Hu]

Hi, Angelo:

On Tue, 2022-01-04 at 10:59 +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).

This patch looks good to me, but please add 'Fixes' tag to note to
which patch this patch want to fix.

Regards,
CK

> 
> Signed-off-by: AngeloGioacchino Del Regno <
> angelogioacchino.delregno@collabora.com>
> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.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;

Re: [PATCH v2] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[CK Hu]

Hi, Angelo:

On Tue, 2022-01-04 at 10:59 +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).

This patch looks good to me, but please add 'Fixes' tag to note to
which patch this patch want to fix.

Regards,
CK

> 
> Signed-off-by: AngeloGioacchino Del Regno <
> angelogioacchino.delregno@collabora.com>
> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.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;


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Linux-mediatek@lists.infradead.org
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Re: [PATCH v2] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[CK Hu]

Hi, Angelo:

On Tue, 2022-01-04 at 10:59 +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).

This patch looks good to me, but please add 'Fixes' tag to note to
which patch this patch want to fix.

Regards,
CK

> 
> Signed-off-by: AngeloGioacchino Del Regno <
> angelogioacchino.delregno@collabora.com>
> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.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;

Re: [PATCH v2] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[CK Hu]

Hi, Angelo:

On Tue, 2022-01-04 at 10:59 +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).

This patch looks good to me, but please add 'Fixes' tag to note to
which patch this patch want to fix.

Regards,
CK

> 
> Signed-off-by: AngeloGioacchino Del Regno <
> angelogioacchino.delregno@collabora.com>
> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.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;


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Re: [PATCH v2] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[AngeloGioacchino Del Regno]

Il 06/01/22 06:22, CK Hu ha scritto:
> Hi, Angelo:
> 
> On Tue, 2022-01-04 at 10:59 +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).
> 
> This patch looks good to me, but please add 'Fixes' tag to note to
> which patch this patch want to fix.
> 
> Regards,
> CK
> 

Hello,
unfortunately I couldn't find a valid commit for a Fixes tag. This
started being an issue at some point, when the DRM API was changed to
adhere to the documented probe sequence: the MediaTek DSI driver was
not the only one that got broken/affected by these changes.

If you have any advice on which commit should be tagged, I'm open for
any kind of suggestion.

Thanks,
- Angelo

Re: [PATCH v2] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[AngeloGioacchino Del Regno]

Il 06/01/22 06:22, CK Hu ha scritto:
> Hi, Angelo:
> 
> On Tue, 2022-01-04 at 10:59 +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).
> 
> This patch looks good to me, but please add 'Fixes' tag to note to
> which patch this patch want to fix.
> 
> Regards,
> CK
> 

Hello,
unfortunately I couldn't find a valid commit for a Fixes tag. This
started being an issue at some point, when the DRM API was changed to
adhere to the documented probe sequence: the MediaTek DSI driver was
not the only one that got broken/affected by these changes.

If you have any advice on which commit should be tagged, I'm open for
any kind of suggestion.

Thanks,
- Angelo

Re: [PATCH v2] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[AngeloGioacchino Del Regno]

Il 06/01/22 06:22, CK Hu ha scritto:
> Hi, Angelo:
> 
> On Tue, 2022-01-04 at 10:59 +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).
> 
> This patch looks good to me, but please add 'Fixes' tag to note to
> which patch this patch want to fix.
> 
> Regards,
> CK
> 

Hello,
unfortunately I couldn't find a valid commit for a Fixes tag. This
started being an issue at some point, when the DRM API was changed to
adhere to the documented probe sequence: the MediaTek DSI driver was
not the only one that got broken/affected by these changes.

If you have any advice on which commit should be tagged, I'm open for
any kind of suggestion.

Thanks,
- Angelo

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

Re: [PATCH v2] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[AngeloGioacchino Del Regno]

Il 06/01/22 06:22, CK Hu ha scritto:
> Hi, Angelo:
> 
> On Tue, 2022-01-04 at 10:59 +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).
> 
> This patch looks good to me, but please add 'Fixes' tag to note to
> which patch this patch want to fix.
> 
> Regards,
> CK
> 

Hello,
unfortunately I couldn't find a valid commit for a Fixes tag. This
started being an issue at some point, when the DRM API was changed to
adhere to the documented probe sequence: the MediaTek DSI driver was
not the only one that got broken/affected by these changes.

If you have any advice on which commit should be tagged, I'm open for
any kind of suggestion.

Thanks,
- Angelo

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

Re: [PATCH v2] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[Jagan Teki]

On Tue, Jan 4, 2022 at 3:30 PM AngeloGioacchino Del Regno
<angelogioacchino.delregno@collabora.com> 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).
>
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
> ---

Eventually I've observed similar issue on other Component based DSI
controllers, hence

Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>

Re: [PATCH v2] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[Jagan Teki]

On Tue, Jan 4, 2022 at 3:30 PM AngeloGioacchino Del Regno
<angelogioacchino.delregno@collabora.com> 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).
>
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
> ---

Eventually I've observed similar issue on other Component based DSI
controllers, hence

Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>

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

Re: [PATCH v2] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[Jagan Teki]

On Tue, Jan 4, 2022 at 3:30 PM AngeloGioacchino Del Regno
<angelogioacchino.delregno@collabora.com> 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).
>
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
> ---

Eventually I've observed similar issue on other Component based DSI
controllers, hence

Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>

Re: [PATCH v2] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[Jagan Teki]

On Tue, Jan 4, 2022 at 3:30 PM AngeloGioacchino Del Regno
<angelogioacchino.delregno@collabora.com> 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).
>
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
> ---

Eventually I've observed similar issue on other Component based DSI
controllers, hence

Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>

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Re: [PATCH v2] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[AngeloGioacchino Del Regno]

Il 12/01/22 08:09, Jagan Teki ha scritto:
> On Tue, Jan 4, 2022 at 3:30 PM AngeloGioacchino Del Regno
> <angelogioacchino.delregno@collabora.com> 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).
>>
>> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
>> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
>> ---
> 
> Eventually I've observed similar issue on other Component based DSI
> controllers, hence
> 
> Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
> 

Hello dri-devel,
can you please pick this patch?

All MediaTek platforms are broken in v5.17 without this one.

Thanks,
Angelo

Re: [PATCH v2] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[AngeloGioacchino Del Regno]

Il 12/01/22 08:09, Jagan Teki ha scritto:
> On Tue, Jan 4, 2022 at 3:30 PM AngeloGioacchino Del Regno
> <angelogioacchino.delregno@collabora.com> 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).
>>
>> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
>> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
>> ---
> 
> Eventually I've observed similar issue on other Component based DSI
> controllers, hence
> 
> Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
> 

Hello dri-devel,
can you please pick this patch?

All MediaTek platforms are broken in v5.17 without this one.

Thanks,
Angelo

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

Re: [PATCH v2] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[AngeloGioacchino Del Regno]

Il 12/01/22 08:09, Jagan Teki ha scritto:
> On Tue, Jan 4, 2022 at 3:30 PM AngeloGioacchino Del Regno
> <angelogioacchino.delregno@collabora.com> 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).
>>
>> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
>> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
>> ---
> 
> Eventually I've observed similar issue on other Component based DSI
> controllers, hence
> 
> Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
> 

Hello dri-devel,
can you please pick this patch?

All MediaTek platforms are broken in v5.17 without this one.

Thanks,
Angelo

Re: [PATCH v2] drm/mediatek: mtk_dsi: Avoid EPROBE_DEFER loop with external bridge

[AngeloGioacchino Del Regno]

Il 12/01/22 08:09, Jagan Teki ha scritto:
> On Tue, Jan 4, 2022 at 3:30 PM AngeloGioacchino Del Regno
> <angelogioacchino.delregno@collabora.com> 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).
>>
>> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
>> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
>> ---
> 
> Eventually I've observed similar issue on other Component based DSI
> controllers, hence
> 
> Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
> 

Hello dri-devel,
can you please pick this patch?

All MediaTek platforms are broken in v5.17 without this one.

Thanks,
Angelo

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

Re: [PATCH v2] 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27日 週四 下午6:32寫道：
>
> Il 12/01/22 08:09, Jagan Teki ha scritto:
> > On Tue, Jan 4, 2022 at 3:30 PM AngeloGioacchino Del Regno
> > <angelogioacchino.delregno@collabora.com> 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).
> >>
> >> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> >> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
> >> ---
> >
> > Eventually I've observed similar issue on other Component based DSI
> > controllers, hence
> >
> > Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
> >
>
> Hello dri-devel,
> can you please pick this patch?
>
> All MediaTek platforms are broken in v5.17 without this one.

Please add Fixes tag [1] to this patch.

[1] https://www.kernel.org/doc/html/v5.16/process/submitting-patches.html

Regards,
Chun-Kuang.

>
> Thanks,
> Angelo

Re: [PATCH v2] 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27日 週四 下午6:32寫道：
>
> Il 12/01/22 08:09, Jagan Teki ha scritto:
> > On Tue, Jan 4, 2022 at 3:30 PM AngeloGioacchino Del Regno
> > <angelogioacchino.delregno@collabora.com> 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).
> >>
> >> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> >> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
> >> ---
> >
> > Eventually I've observed similar issue on other Component based DSI
> > controllers, hence
> >
> > Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
> >
>
> Hello dri-devel,
> can you please pick this patch?
>
> All MediaTek platforms are broken in v5.17 without this one.

Please add Fixes tag [1] to this patch.

[1] https://www.kernel.org/doc/html/v5.16/process/submitting-patches.html

Regards,
Chun-Kuang.

>
> Thanks,
> Angelo

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

Re: [PATCH v2] 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27日 週四 下午6:32寫道：
>
> Il 12/01/22 08:09, Jagan Teki ha scritto:
> > On Tue, Jan 4, 2022 at 3:30 PM AngeloGioacchino Del Regno
> > <angelogioacchino.delregno@collabora.com> 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).
> >>
> >> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> >> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
> >> ---
> >
> > Eventually I've observed similar issue on other Component based DSI
> > controllers, hence
> >
> > Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
> >
>
> Hello dri-devel,
> can you please pick this patch?
>
> All MediaTek platforms are broken in v5.17 without this one.

Please add Fixes tag [1] to this patch.

[1] https://www.kernel.org/doc/html/v5.16/process/submitting-patches.html

Regards,
Chun-Kuang.

>
> Thanks,
> Angelo

Re: [PATCH v2] 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27日 週四 下午6:32寫道：
>
> Il 12/01/22 08:09, Jagan Teki ha scritto:
> > On Tue, Jan 4, 2022 at 3:30 PM AngeloGioacchino Del Regno
> > <angelogioacchino.delregno@collabora.com> 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).
> >>
> >> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> >> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
> >> ---
> >
> > Eventually I've observed similar issue on other Component based DSI
> > controllers, hence
> >
> > Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
> >
>
> Hello dri-devel,
> can you please pick this patch?
>
> All MediaTek platforms are broken in v5.17 without this one.

Please add Fixes tag [1] to this patch.

[1] https://www.kernel.org/doc/html/v5.16/process/submitting-patches.html

Regards,
Chun-Kuang.

>
> Thanks,
> Angelo

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