[PATCH v2 0/5] drm: Ignore non-existing color planes in helpers

[PATCH v2 0/5] drm: Ignore non-existing color planes in helpers

[Thomas Zimmermann]

Some DRM helpers assume that all potential color planes of a framebuffer
are available; even if the color format didn't specify them. Non-existing
planes are silently ignored. This behavior is inconsistent with other
helpers and apparently leads to subtle bugs with uninitialized GEM buffer
mappings. [1]

Change all affected code to look at the framebuffer format's number of
color planes and only process these planes. The update has been discussed
in [2] before.

Tested with GEM SHMEM helpers on simpledrm and with GEM VRAM helpers on
ast.

v2:
	* refactor GEM VRAM code before fixing it (Javier)
	* print more error information in #1 (Javier)
	* commit-message fixes (Javier)

[1] https://lore.kernel.org/dri-devel/20210730183511.20080-1-tzimmermann@suse.de/T/#md0172b10bb588d8f20f4f456e304f08d2a4505f7
[2] https://lore.kernel.org/dri-devel/877dc0d9-c6c6-022c-20d8-14b33e863934@suse.de/

Thomas Zimmermann (5):
  drm/gem: Share code between drm_gem_fb_{begin,end}_cpu_access()
  drm/gem: Ignore color planes that are unused by framebuffer format
  drm/gem-vram: Share code between GEM VRAM's _{prepare,cleanup}_fb()
  drm/gem-vram: Ignore planes that are unused by framebuffer format
  drm/gem: Warn on trying to use a non-existing framebuffer plane

 drivers/gpu/drm/drm_gem_atomic_helper.c      |   6 +-
 drivers/gpu/drm/drm_gem_framebuffer_helper.c | 104 +++++++++----------
 drivers/gpu/drm/drm_gem_vram_helper.c        |  54 ++++++----
 include/drm/drm_gem_framebuffer_helper.h     |  10 +-
 4 files changed, 92 insertions(+), 82 deletions(-)

-- 
2.36.1

[PATCH v2 1/5] drm/gem: Share code between drm_gem_fb_{begin, end}_cpu_access()

[Thomas Zimmermann]

The error-recovery code in drm_gem_fb_begin() is of the same pattern
as drm_gem_fb_end(). Implement both of them using an internal helper.
No functional changes.

v2:
	* print additional information in error message (Javier)
	* fix commit description (Javier)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Tested-by: Noralf Trønnes <noralf@tronnes.org>
---
 drivers/gpu/drm/drm_gem_framebuffer_helper.c | 63 +++++++++-----------
 1 file changed, 27 insertions(+), 36 deletions(-)

diff --git a/drivers/gpu/drm/drm_gem_framebuffer_helper.c b/drivers/gpu/drm/drm_gem_framebuffer_helper.c
index f4619803acd0..931828784dfe 100644
--- a/drivers/gpu/drm/drm_gem_framebuffer_helper.c
+++ b/drivers/gpu/drm/drm_gem_framebuffer_helper.c
@@ -403,6 +403,28 @@ void drm_gem_fb_vunmap(struct drm_framebuffer *fb,
 }
 EXPORT_SYMBOL(drm_gem_fb_vunmap);
 
+static void __drm_gem_fb_end_cpu_access(struct drm_framebuffer *fb, enum dma_data_direction dir,
+					unsigned int num_planes)
+{
+	struct dma_buf_attachment *import_attach;
+	struct drm_gem_object *obj;
+	int ret;
+
+	while (num_planes) {
+		--num_planes;
+		obj = drm_gem_fb_get_obj(fb, num_planes);
+		if (!obj)
+			continue;
+		import_attach = obj->import_attach;
+		if (!import_attach)
+			continue;
+		ret = dma_buf_end_cpu_access(import_attach->dmabuf, dir);
+		if (ret)
+			drm_err(fb->dev, "dma_buf_end_cpu_access(%u, %d) failed: %d\n",
+				ret, num_planes, dir);
+	}
+}
+
 /**
  * drm_gem_fb_begin_cpu_access - prepares GEM buffer objects for CPU access
  * @fb: the framebuffer
@@ -422,7 +444,7 @@ int drm_gem_fb_begin_cpu_access(struct drm_framebuffer *fb, enum dma_data_direct
 	struct dma_buf_attachment *import_attach;
 	struct drm_gem_object *obj;
 	size_t i;
-	int ret, ret2;
+	int ret;
 
 	for (i = 0; i < ARRAY_SIZE(fb->obj); ++i) {
 		obj = drm_gem_fb_get_obj(fb, i);
@@ -433,28 +455,13 @@ int drm_gem_fb_begin_cpu_access(struct drm_framebuffer *fb, enum dma_data_direct
 			continue;
 		ret = dma_buf_begin_cpu_access(import_attach->dmabuf, dir);
 		if (ret)
-			goto err_dma_buf_end_cpu_access;
+			goto err___drm_gem_fb_end_cpu_access;
 	}
 
 	return 0;
 
-err_dma_buf_end_cpu_access:
-	while (i) {
-		--i;
-		obj = drm_gem_fb_get_obj(fb, i);
-		if (!obj)
-			continue;
-		import_attach = obj->import_attach;
-		if (!import_attach)
-			continue;
-		ret2 = dma_buf_end_cpu_access(import_attach->dmabuf, dir);
-		if (ret2) {
-			drm_err(fb->dev,
-				"dma_buf_end_cpu_access() failed during error handling: %d\n",
-				ret2);
-		}
-	}
-
+err___drm_gem_fb_end_cpu_access:
+	__drm_gem_fb_end_cpu_access(fb, dir, i);
 	return ret;
 }
 EXPORT_SYMBOL(drm_gem_fb_begin_cpu_access);
@@ -472,23 +479,7 @@ EXPORT_SYMBOL(drm_gem_fb_begin_cpu_access);
  */
 void drm_gem_fb_end_cpu_access(struct drm_framebuffer *fb, enum dma_data_direction dir)
 {
-	size_t i = ARRAY_SIZE(fb->obj);
-	struct dma_buf_attachment *import_attach;
-	struct drm_gem_object *obj;
-	int ret;
-
-	while (i) {
-		--i;
-		obj = drm_gem_fb_get_obj(fb, i);
-		if (!obj)
-			continue;
-		import_attach = obj->import_attach;
-		if (!import_attach)
-			continue;
-		ret = dma_buf_end_cpu_access(import_attach->dmabuf, dir);
-		if (ret)
-			drm_err(fb->dev, "dma_buf_end_cpu_access() failed: %d\n", ret);
-	}
+	__drm_gem_fb_end_cpu_access(fb, dir, ARRAY_SIZE(fb->obj));
 }
 EXPORT_SYMBOL(drm_gem_fb_end_cpu_access);
 
-- 
2.36.1

[PATCH v2 2/5] drm/gem: Ignore color planes that are unused by framebuffer format

[Thomas Zimmermann]

Only handle color planes that exist in a framebuffer's color format.
Ignore non-existing planes.

So far, several helpers assumed that all 4 planes are available and
silently ignored non-existing planes. This lead to subtil bugs with
uninitialized data in instances of struct iosys_map. [1]

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Tested-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://lore.kernel.org/dri-devel/20210730183511.20080-1-tzimmermann@suse.de/T/#md0172b10bb588d8f20f4f456e304f08d2a4505f7 # 1
---
 drivers/gpu/drm/drm_gem_atomic_helper.c      |  6 ++--
 drivers/gpu/drm/drm_gem_framebuffer_helper.c | 37 +++++++++++---------
 include/drm/drm_gem_framebuffer_helper.h     | 10 ++----
 3 files changed, 27 insertions(+), 26 deletions(-)

diff --git a/drivers/gpu/drm/drm_gem_atomic_helper.c b/drivers/gpu/drm/drm_gem_atomic_helper.c
index a5026f617739..f16d60217c6c 100644
--- a/drivers/gpu/drm/drm_gem_atomic_helper.c
+++ b/drivers/gpu/drm/drm_gem_atomic_helper.c
@@ -169,8 +169,10 @@ int drm_gem_plane_helper_prepare_fb(struct drm_plane *plane,
 		struct drm_gem_object *obj = drm_gem_fb_get_obj(state->fb, i);
 		struct dma_fence *new;
 
-		if (WARN_ON_ONCE(!obj))
-			continue;
+		if (!obj) {
+			ret = -EINVAL;
+			goto error;
+		}
 
 		ret = dma_resv_get_singleton(obj->resv, usage, &new);
 		if (ret)
diff --git a/drivers/gpu/drm/drm_gem_framebuffer_helper.c b/drivers/gpu/drm/drm_gem_framebuffer_helper.c
index 931828784dfe..6d3c26efdeeb 100644
--- a/drivers/gpu/drm/drm_gem_framebuffer_helper.c
+++ b/drivers/gpu/drm/drm_gem_framebuffer_helper.c
@@ -92,9 +92,9 @@ drm_gem_fb_init(struct drm_device *dev,
  */
 void drm_gem_fb_destroy(struct drm_framebuffer *fb)
 {
-	size_t i;
+	unsigned int i;
 
-	for (i = 0; i < ARRAY_SIZE(fb->obj); i++)
+	for (i = 0; i < fb->format->num_planes; i++)
 		drm_gem_object_put(fb->obj[i]);
 
 	drm_framebuffer_cleanup(fb);
@@ -329,24 +329,26 @@ EXPORT_SYMBOL_GPL(drm_gem_fb_create_with_dirty);
  * The argument returns the addresses of the data stored in each BO. This
  * is different from @map if the framebuffer's offsets field is non-zero.
  *
+ * Both, @map and @data, must each refer to arrays with at least
+ * fb->format->num_planes elements.
+ *
  * See drm_gem_fb_vunmap() for unmapping.
  *
  * Returns:
  * 0 on success, or a negative errno code otherwise.
  */
-int drm_gem_fb_vmap(struct drm_framebuffer *fb,
-		    struct iosys_map map[static DRM_FORMAT_MAX_PLANES],
-		    struct iosys_map data[DRM_FORMAT_MAX_PLANES])
+int drm_gem_fb_vmap(struct drm_framebuffer *fb, struct iosys_map *map,
+		    struct iosys_map *data)
 {
 	struct drm_gem_object *obj;
 	unsigned int i;
 	int ret;
 
-	for (i = 0; i < DRM_FORMAT_MAX_PLANES; ++i) {
+	for (i = 0; i < fb->format->num_planes; ++i) {
 		obj = drm_gem_fb_get_obj(fb, i);
 		if (!obj) {
-			iosys_map_clear(&map[i]);
-			continue;
+			ret = -EINVAL;
+			goto err_drm_gem_vunmap;
 		}
 		ret = drm_gem_vmap(obj, &map[i]);
 		if (ret)
@@ -354,7 +356,7 @@ int drm_gem_fb_vmap(struct drm_framebuffer *fb,
 	}
 
 	if (data) {
-		for (i = 0; i < DRM_FORMAT_MAX_PLANES; ++i) {
+		for (i = 0; i < fb->format->num_planes; ++i) {
 			memcpy(&data[i], &map[i], sizeof(data[i]));
 			if (iosys_map_is_null(&data[i]))
 				continue;
@@ -385,10 +387,9 @@ EXPORT_SYMBOL(drm_gem_fb_vmap);
  *
  * See drm_gem_fb_vmap() for more information.
  */
-void drm_gem_fb_vunmap(struct drm_framebuffer *fb,
-		       struct iosys_map map[static DRM_FORMAT_MAX_PLANES])
+void drm_gem_fb_vunmap(struct drm_framebuffer *fb, struct iosys_map *map)
 {
-	unsigned int i = DRM_FORMAT_MAX_PLANES;
+	unsigned int i = fb->format->num_planes;
 	struct drm_gem_object *obj;
 
 	while (i) {
@@ -443,13 +444,15 @@ int drm_gem_fb_begin_cpu_access(struct drm_framebuffer *fb, enum dma_data_direct
 {
 	struct dma_buf_attachment *import_attach;
 	struct drm_gem_object *obj;
-	size_t i;
+	unsigned int i;
 	int ret;
 
-	for (i = 0; i < ARRAY_SIZE(fb->obj); ++i) {
+	for (i = 0; i < fb->format->num_planes; ++i) {
 		obj = drm_gem_fb_get_obj(fb, i);
-		if (!obj)
-			continue;
+		if (!obj) {
+			ret = -EINVAL;
+			goto err___drm_gem_fb_end_cpu_access;
+		}
 		import_attach = obj->import_attach;
 		if (!import_attach)
 			continue;
@@ -479,7 +482,7 @@ EXPORT_SYMBOL(drm_gem_fb_begin_cpu_access);
  */
 void drm_gem_fb_end_cpu_access(struct drm_framebuffer *fb, enum dma_data_direction dir)
 {
-	__drm_gem_fb_end_cpu_access(fb, dir, ARRAY_SIZE(fb->obj));
+	__drm_gem_fb_end_cpu_access(fb, dir, fb->format->num_planes);
 }
 EXPORT_SYMBOL(drm_gem_fb_end_cpu_access);
 
diff --git a/include/drm/drm_gem_framebuffer_helper.h b/include/drm/drm_gem_framebuffer_helper.h
index 1091e4fa08cb..d302521f3dd4 100644
--- a/include/drm/drm_gem_framebuffer_helper.h
+++ b/include/drm/drm_gem_framebuffer_helper.h
@@ -4,8 +4,6 @@
 #include <linux/dma-buf.h>
 #include <linux/iosys-map.h>
 
-#include <drm/drm_fourcc.h>
-
 struct drm_afbc_framebuffer;
 struct drm_device;
 struct drm_fb_helper_surface_size;
@@ -39,11 +37,9 @@ struct drm_framebuffer *
 drm_gem_fb_create_with_dirty(struct drm_device *dev, struct drm_file *file,
 			     const struct drm_mode_fb_cmd2 *mode_cmd);
 
-int drm_gem_fb_vmap(struct drm_framebuffer *fb,
-		    struct iosys_map map[static DRM_FORMAT_MAX_PLANES],
-		    struct iosys_map data[DRM_FORMAT_MAX_PLANES]);
-void drm_gem_fb_vunmap(struct drm_framebuffer *fb,
-		       struct iosys_map map[static DRM_FORMAT_MAX_PLANES]);
+int drm_gem_fb_vmap(struct drm_framebuffer *fb, struct iosys_map *map,
+		    struct iosys_map *data);
+void drm_gem_fb_vunmap(struct drm_framebuffer *fb, struct iosys_map *map);
 int drm_gem_fb_begin_cpu_access(struct drm_framebuffer *fb, enum dma_data_direction dir);
 void drm_gem_fb_end_cpu_access(struct drm_framebuffer *fb, enum dma_data_direction dir);
 
-- 
2.36.1

[PATCH v2 3/5] drm/gem-vram: Share code between GEM VRAM's _{prepare, cleanup}_fb()

[Thomas Zimmermann]

The error-recovery code in drm_gem_vram_plane_helper_prepare_fb() is of
the same pattern as drm_gem_vram_plane_helper_cleanup_fb(). Implement
both of them using an internal helper. No functional changes.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/gpu/drm/drm_gem_vram_helper.c | 37 +++++++++++++++++----------
 1 file changed, 23 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/drm_gem_vram_helper.c b/drivers/gpu/drm/drm_gem_vram_helper.c
index 123045b58fec..566d139f0fa0 100644
--- a/drivers/gpu/drm/drm_gem_vram_helper.c
+++ b/drivers/gpu/drm/drm_gem_vram_helper.c
@@ -9,6 +9,7 @@
 #include <drm/drm_file.h>
 #include <drm/drm_framebuffer.h>
 #include <drm/drm_gem_atomic_helper.h>
+#include <drm/drm_gem_framebuffer_helper.h>
 #include <drm/drm_gem_ttm_helper.h>
 #include <drm/drm_gem_vram_helper.h>
 #include <drm/drm_managed.h>
@@ -630,6 +631,24 @@ EXPORT_SYMBOL(drm_gem_vram_driver_dumb_create);
  * Helpers for struct drm_plane_helper_funcs
  */
 
+static void __drm_gem_vram_plane_helper_cleanup_fb(struct drm_plane *plane,
+						   struct drm_plane_state *state,
+						   unsigned int num_planes)
+{
+	struct drm_gem_object *obj;
+	struct drm_gem_vram_object *gbo;
+	struct drm_framebuffer *fb = state->fb;
+
+	while (num_planes) {
+		--num_planes;
+		obj = drm_gem_fb_get_obj(fb, num_planes);
+		if (!obj)
+			continue;
+		gbo = drm_gem_vram_of_gem(obj);
+		drm_gem_vram_unpin(gbo);
+	}
+}
+
 /**
  * drm_gem_vram_plane_helper_prepare_fb() - \
  *	Implements &struct drm_plane_helper_funcs.prepare_fb
@@ -671,11 +690,7 @@ drm_gem_vram_plane_helper_prepare_fb(struct drm_plane *plane,
 	return 0;
 
 err_drm_gem_vram_unpin:
-	while (i) {
-		--i;
-		gbo = drm_gem_vram_of_gem(new_state->fb->obj[i]);
-		drm_gem_vram_unpin(gbo);
-	}
+	__drm_gem_vram_plane_helper_cleanup_fb(plane, new_state, i);
 	return ret;
 }
 EXPORT_SYMBOL(drm_gem_vram_plane_helper_prepare_fb);
@@ -694,18 +709,12 @@ void
 drm_gem_vram_plane_helper_cleanup_fb(struct drm_plane *plane,
 				     struct drm_plane_state *old_state)
 {
-	size_t i;
-	struct drm_gem_vram_object *gbo;
+	struct drm_framebuffer *fb = old_state->fb;
 
-	if (!old_state->fb)
+	if (!fb)
 		return;
 
-	for (i = 0; i < ARRAY_SIZE(old_state->fb->obj); ++i) {
-		if (!old_state->fb->obj[i])
-			continue;
-		gbo = drm_gem_vram_of_gem(old_state->fb->obj[i]);
-		drm_gem_vram_unpin(gbo);
-	}
+	__drm_gem_vram_plane_helper_cleanup_fb(plane, old_state, ARRAY_SIZE(fb->obj));
 }
 EXPORT_SYMBOL(drm_gem_vram_plane_helper_cleanup_fb);
 
-- 
2.36.1

Re: [PATCH v2 3/5] drm/gem-vram: Share code between GEM VRAM's _{prepare,cleanup}_fb()

[Javier Martinez Canillas]

Hello Thomas,

On 5/17/22 13:33, Thomas Zimmermann wrote:
> The error-recovery code in drm_gem_vram_plane_helper_prepare_fb() is of
> the same pattern as drm_gem_vram_plane_helper_cleanup_fb(). Implement
> both of them using an internal helper. No functional changes.
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---

Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>

-- 
Best regards,

Javier Martinez Canillas
Linux Engineering
Red Hat

[PATCH v2 4/5] drm/gem-vram: Ignore planes that are unused by framebuffer format

[Thomas Zimmermann]

Only handle color planes that exist in a framebuffer's color format.
Ignore non-existing planes.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Tested-by: Noralf Trønnes <noralf@tronnes.org>
---
 drivers/gpu/drm/drm_gem_vram_helper.c | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/drm_gem_vram_helper.c b/drivers/gpu/drm/drm_gem_vram_helper.c
index 566d139f0fa0..d607043716d3 100644
--- a/drivers/gpu/drm/drm_gem_vram_helper.c
+++ b/drivers/gpu/drm/drm_gem_vram_helper.c
@@ -667,17 +667,22 @@ int
 drm_gem_vram_plane_helper_prepare_fb(struct drm_plane *plane,
 				     struct drm_plane_state *new_state)
 {
-	size_t i;
+	struct drm_framebuffer *fb = new_state->fb;
 	struct drm_gem_vram_object *gbo;
+	struct drm_gem_object *obj;
+	unsigned int i;
 	int ret;
 
-	if (!new_state->fb)
+	if (!fb)
 		return 0;
 
-	for (i = 0; i < ARRAY_SIZE(new_state->fb->obj); ++i) {
-		if (!new_state->fb->obj[i])
-			continue;
-		gbo = drm_gem_vram_of_gem(new_state->fb->obj[i]);
+	for (i = 0; i < fb->format->num_planes; ++i) {
+		obj = drm_gem_fb_get_obj(fb, i);
+		if (!obj) {
+			ret = -EINVAL;
+			goto err_drm_gem_vram_unpin;
+		}
+		gbo = drm_gem_vram_of_gem(obj);
 		ret = drm_gem_vram_pin(gbo, DRM_GEM_VRAM_PL_FLAG_VRAM);
 		if (ret)
 			goto err_drm_gem_vram_unpin;
@@ -714,7 +719,7 @@ drm_gem_vram_plane_helper_cleanup_fb(struct drm_plane *plane,
 	if (!fb)
 		return;
 
-	__drm_gem_vram_plane_helper_cleanup_fb(plane, old_state, ARRAY_SIZE(fb->obj));
+	__drm_gem_vram_plane_helper_cleanup_fb(plane, old_state, fb->format->num_planes);
 }
 EXPORT_SYMBOL(drm_gem_vram_plane_helper_cleanup_fb);
 
-- 
2.36.1

[PATCH v2 5/5] drm/gem: Warn on trying to use a non-existing framebuffer plane

[Thomas Zimmermann]

Warn if callers of drm_gem_fb_get_obj() try to use a GEM buffer for
a non-existing or unset plane.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Tested-by: Noralf Trønnes <noralf@tronnes.org>
---
 drivers/gpu/drm/drm_gem_framebuffer_helper.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_gem_framebuffer_helper.c b/drivers/gpu/drm/drm_gem_framebuffer_helper.c
index 6d3c26efdeeb..61339a9cd010 100644
--- a/drivers/gpu/drm/drm_gem_framebuffer_helper.c
+++ b/drivers/gpu/drm/drm_gem_framebuffer_helper.c
@@ -53,7 +53,11 @@ MODULE_IMPORT_NS(DMA_BUF);
 struct drm_gem_object *drm_gem_fb_get_obj(struct drm_framebuffer *fb,
 					  unsigned int plane)
 {
-	if (plane >= ARRAY_SIZE(fb->obj))
+	struct drm_device *dev = fb->dev;
+
+	if (drm_WARN_ON_ONCE(dev, plane >= ARRAY_SIZE(fb->obj)))
+		return NULL;
+	else if (drm_WARN_ON_ONCE(dev, !fb->obj[plane]))
 		return NULL;
 
 	return fb->obj[plane];
-- 
2.36.1

Re: [PATCH v2 0/5] drm: Ignore non-existing color planes in helpers

[Christian König]

Am 17.05.22 um 13:33 schrieb Thomas Zimmermann:
> Some DRM helpers assume that all potential color planes of a framebuffer
> are available; even if the color format didn't specify them. Non-existing
> planes are silently ignored. This behavior is inconsistent with other
> helpers and apparently leads to subtle bugs with uninitialized GEM buffer
> mappings. [1]
>
> Change all affected code to look at the framebuffer format's number of
> color planes and only process these planes. The update has been discussed
> in [2] before.
>
> Tested with GEM SHMEM helpers on simpledrm and with GEM VRAM helpers on
> ast.

I'm not deep enough into all the details for a full review, but feel 
free to add an Acked-by: Christian König <christian.koenig@amd.com> to 
the series.

Thanks,
Christian.

>
> v2:
> 	* refactor GEM VRAM code before fixing it (Javier)
> 	* print more error information in #1 (Javier)
> 	* commit-message fixes (Javier)
>
> [1] https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fdri-devel%2F20210730183511.20080-1-tzimmermann%40suse.de%2FT%2F%23md0172b10bb588d8f20f4f456e304f08d2a4505f7&amp;data=05%7C01%7Cchristian.koenig%40amd.com%7Cc512a92c206f4af0691108da37f915a1%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637883840259373791%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=6fXRY%2BWlo1I47tcuRHiamAZ9JGM%2FHaYTfyGnxNrqUts%3D&amp;reserved=0
> [2] https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fdri-devel%2F877dc0d9-c6c6-022c-20d8-14b33e863934%40suse.de%2F&amp;data=05%7C01%7Cchristian.koenig%40amd.com%7Cc512a92c206f4af0691108da37f915a1%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637883840259373791%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=6iFYw5EtQNaSiPrHIAawBw87lj6M66o7j0ADY0ipifs%3D&amp;reserved=0
>
> Thomas Zimmermann (5):
>    drm/gem: Share code between drm_gem_fb_{begin,end}_cpu_access()
>    drm/gem: Ignore color planes that are unused by framebuffer format
>    drm/gem-vram: Share code between GEM VRAM's _{prepare,cleanup}_fb()
>    drm/gem-vram: Ignore planes that are unused by framebuffer format
>    drm/gem: Warn on trying to use a non-existing framebuffer plane
>
>   drivers/gpu/drm/drm_gem_atomic_helper.c      |   6 +-
>   drivers/gpu/drm/drm_gem_framebuffer_helper.c | 104 +++++++++----------
>   drivers/gpu/drm/drm_gem_vram_helper.c        |  54 ++++++----
>   include/drm/drm_gem_framebuffer_helper.h     |  10 +-
>   4 files changed, 92 insertions(+), 82 deletions(-)
>

Re: [PATCH v2 0/5] drm: Ignore non-existing color planes in helpers

[Thomas Zimmermann]

[-- Attachment #1.1: Type: text/plain, Size: 3209 bytes --]

Hi

Am 17.05.22 um 13:56 schrieb Christian König:
> Am 17.05.22 um 13:33 schrieb Thomas Zimmermann:
>> Some DRM helpers assume that all potential color planes of a framebuffer
>> are available; even if the color format didn't specify them. Non-existing
>> planes are silently ignored. This behavior is inconsistent with other
>> helpers and apparently leads to subtle bugs with uninitialized GEM buffer
>> mappings. [1]
>>
>> Change all affected code to look at the framebuffer format's number of
>> color planes and only process these planes. The update has been discussed
>> in [2] before.
>>
>> Tested with GEM SHMEM helpers on simpledrm and with GEM VRAM helpers on
>> ast.
> 
> I'm not deep enough into all the details for a full review, but feel 
> free to add an Acked-by: Christian König <christian.koenig@amd.com> to 
> the series.

Thanks a lot. I cc'ed you because we recently talked about the 
inconsistent use of num_planes throughout the DRM helpers.

Best regards
Thomas

> 
> Thanks,
> Christian.
> 
>>
>> v2:
>>     * refactor GEM VRAM code before fixing it (Javier)
>>     * print more error information in #1 (Javier)
>>     * commit-message fixes (Javier)
>>
>> [1] 
>> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fdri-devel%2F20210730183511.20080-1-tzimmermann%40suse.de%2FT%2F%23md0172b10bb588d8f20f4f456e304f08d2a4505f7&amp;data=05%7C01%7Cchristian.koenig%40amd.com%7Cc512a92c206f4af0691108da37f915a1%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637883840259373791%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=6fXRY%2BWlo1I47tcuRHiamAZ9JGM%2FHaYTfyGnxNrqUts%3D&amp;reserved=0 
>>
>> [2] 
>> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.kernel.org%2Fdri-devel%2F877dc0d9-c6c6-022c-20d8-14b33e863934%40suse.de%2F&amp;data=05%7C01%7Cchristian.koenig%40amd.com%7Cc512a92c206f4af0691108da37f915a1%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637883840259373791%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=6iFYw5EtQNaSiPrHIAawBw87lj6M66o7j0ADY0ipifs%3D&amp;reserved=0 
>>
>>
>> Thomas Zimmermann (5):
>>    drm/gem: Share code between drm_gem_fb_{begin,end}_cpu_access()
>>    drm/gem: Ignore color planes that are unused by framebuffer format
>>    drm/gem-vram: Share code between GEM VRAM's _{prepare,cleanup}_fb()
>>    drm/gem-vram: Ignore planes that are unused by framebuffer format
>>    drm/gem: Warn on trying to use a non-existing framebuffer plane
>>
>>   drivers/gpu/drm/drm_gem_atomic_helper.c      |   6 +-
>>   drivers/gpu/drm/drm_gem_framebuffer_helper.c | 104 +++++++++----------
>>   drivers/gpu/drm/drm_gem_vram_helper.c        |  54 ++++++----
>>   include/drm/drm_gem_framebuffer_helper.h     |  10 +-
>>   4 files changed, 92 insertions(+), 82 deletions(-)
>>
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev

[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 840 bytes --]