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From: Robin Murphy <robin.murphy@arm.com>
To: chunkuang.hu@kernel.org, p.zabel@pengutronix.de
Cc: yong.wu@mediatek.com, airlied@gmail.com, daniel@ffwll.ch,
	matthias.bgg@gmail.com, angelogioacchino.delregno@collabora.com,
	dri-devel@lists.freedesktop.org,
	linux-mediatek@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3] drm/mediatek: Stop using iommu_present()
Date: Thu, 23 Nov 2023 13:41:12 +0000	[thread overview]
Message-ID: <fd1b62aa006556f29f37535814abfe41be63f7ae.1700746094.git.robin.murphy@arm.com> (raw)

Remove the pointless check. If an IOMMU is providing transparent DMA API
ops for any device(s) we care about, the DT code will have enforced the
appropriate probe ordering already. And if the IOMMU *is* entirely
absent, then attempting to go ahead with CMA and either suceeding or
failing decisively seems more useful than deferring forever.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---

I realised that last time I sent this I probably should have CCed a
wider audience of reviewers, so here's one with an updated commit
message as well to make the resend more worthwhile.

 drivers/gpu/drm/mediatek/mtk_drm_drv.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
index 2dfaa613276a..48581da51857 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
@@ -5,7 +5,6 @@
  */
 
 #include <linux/component.h>
-#include <linux/iommu.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
@@ -608,9 +607,6 @@ static int mtk_drm_bind(struct device *dev)
 	struct drm_device *drm;
 	int ret, i;
 
-	if (!iommu_present(&platform_bus_type))
-		return -EPROBE_DEFER;
-
 	pdev = of_find_device_by_node(private->mutex_node);
 	if (!pdev) {
 		dev_err(dev, "Waiting for disp-mutex device %pOF\n",
-- 
2.39.2.101.g768bb238c484.dirty



WARNING: multiple messages have this Message-ID (diff)
From: Robin Murphy <robin.murphy@arm.com>
To: chunkuang.hu@kernel.org, p.zabel@pengutronix.de
Cc: yong.wu@mediatek.com, airlied@gmail.com, daniel@ffwll.ch,
	matthias.bgg@gmail.com, angelogioacchino.delregno@collabora.com,
	dri-devel@lists.freedesktop.org,
	linux-mediatek@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3] drm/mediatek: Stop using iommu_present()
Date: Thu, 23 Nov 2023 13:41:12 +0000	[thread overview]
Message-ID: <fd1b62aa006556f29f37535814abfe41be63f7ae.1700746094.git.robin.murphy@arm.com> (raw)

Remove the pointless check. If an IOMMU is providing transparent DMA API
ops for any device(s) we care about, the DT code will have enforced the
appropriate probe ordering already. And if the IOMMU *is* entirely
absent, then attempting to go ahead with CMA and either suceeding or
failing decisively seems more useful than deferring forever.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---

I realised that last time I sent this I probably should have CCed a
wider audience of reviewers, so here's one with an updated commit
message as well to make the resend more worthwhile.

 drivers/gpu/drm/mediatek/mtk_drm_drv.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
index 2dfaa613276a..48581da51857 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
@@ -5,7 +5,6 @@
  */
 
 #include <linux/component.h>
-#include <linux/iommu.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
@@ -608,9 +607,6 @@ static int mtk_drm_bind(struct device *dev)
 	struct drm_device *drm;
 	int ret, i;
 
-	if (!iommu_present(&platform_bus_type))
-		return -EPROBE_DEFER;
-
 	pdev = of_find_device_by_node(private->mutex_node);
 	if (!pdev) {
 		dev_err(dev, "Waiting for disp-mutex device %pOF\n",
-- 
2.39.2.101.g768bb238c484.dirty


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

WARNING: multiple messages have this Message-ID (diff)
From: Robin Murphy <robin.murphy@arm.com>
To: chunkuang.hu@kernel.org, p.zabel@pengutronix.de
Cc: dri-devel@lists.freedesktop.org,
	linux-mediatek@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org, matthias.bgg@gmail.com,
	yong.wu@mediatek.com, angelogioacchino.delregno@collabora.com
Subject: [PATCH v3] drm/mediatek: Stop using iommu_present()
Date: Thu, 23 Nov 2023 13:41:12 +0000	[thread overview]
Message-ID: <fd1b62aa006556f29f37535814abfe41be63f7ae.1700746094.git.robin.murphy@arm.com> (raw)

Remove the pointless check. If an IOMMU is providing transparent DMA API
ops for any device(s) we care about, the DT code will have enforced the
appropriate probe ordering already. And if the IOMMU *is* entirely
absent, then attempting to go ahead with CMA and either suceeding or
failing decisively seems more useful than deferring forever.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---

I realised that last time I sent this I probably should have CCed a
wider audience of reviewers, so here's one with an updated commit
message as well to make the resend more worthwhile.

 drivers/gpu/drm/mediatek/mtk_drm_drv.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
index 2dfaa613276a..48581da51857 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
@@ -5,7 +5,6 @@
  */
 
 #include <linux/component.h>
-#include <linux/iommu.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
@@ -608,9 +607,6 @@ static int mtk_drm_bind(struct device *dev)
 	struct drm_device *drm;
 	int ret, i;
 
-	if (!iommu_present(&platform_bus_type))
-		return -EPROBE_DEFER;
-
 	pdev = of_find_device_by_node(private->mutex_node);
 	if (!pdev) {
 		dev_err(dev, "Waiting for disp-mutex device %pOF\n",
-- 
2.39.2.101.g768bb238c484.dirty


             reply	other threads:[~2023-11-23 13:41 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-23 13:41 Robin Murphy [this message]
2023-11-23 13:41 ` [PATCH v3] drm/mediatek: Stop using iommu_present() Robin Murphy
2023-11-23 13:41 ` Robin Murphy
2023-11-27  8:56 ` AngeloGioacchino Del Regno
2023-11-27  8:56   ` AngeloGioacchino Del Regno
2023-11-27  8:56   ` AngeloGioacchino Del Regno
2023-12-07 23:31 ` Chun-Kuang Hu
2023-12-07 23:31   ` Chun-Kuang Hu
2023-12-07 23:31   ` Chun-Kuang Hu

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