From: Rob Herring <robh@kernel.org>
In preparation to allow DRM DMA users to adjust the DMA_ATTR_* flags,
convert the DMA helper code to use the dma_*_attr APIs instead of the
dma_*_wc variants.
Only the DMA_ATTR_WRITE_COMBINE and DMA_ATTR_NO_WARN attributes are set
in this commit, so there's no functional change.
Update rcar_du_vsp_map_fb() to use dma_get_sgtable_attrs() instead of
dma_get_sgtable().
Also change the dma_free_wc() call in vc4_bo_purge() in the vc4 driver
to use dma_free_attrs() to match. vc4_bo is a sub-class of
drm_gem_dma_object.
Sub-classes of |struct drm_gem_dma_object| can also set additional
DMA_ATTR_* flags if they choose so. For example a sub-class could
set DMA_ATTR_FORCE_CONTIGUOUS in certain cases.
Signed-off-by: Rob Herring <robh@kernel.org>
[wenst@chromium.org: Rebase onto renamed DMA helpers]
[wenst@chromium.org: Make vc4_bo_purge() use matching dma_free_attrs()]
[wenst@chromium.org: Make rcar_du_vsp_map_fb() use dma_get_sgtable_attrs()]
[wenst@chromium.org: Expand commit message to mention that sub-classes
can set extra DMA_ATTR_* flags]
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
---
Changes since v2:
- rcar-du: Change dma_get_sgtable() to dma_get_sgtable_attrs()
Changes since v1:
- Rebased onto renamed DMA helpers
- Made vc4_bo_purge() use matching dma_free_attrs()
- Expanded commit message to mention that sub-classes can set extra
DMA_ATTR_* flags
---
drivers/gpu/drm/drm_gem_dma_helper.c | 26 +++++++++++--------
drivers/gpu/drm/renesas/rcar-du/rcar_du_vsp.c | 5 ++--
drivers/gpu/drm/vc4/vc4_bo.c | 2 +-
include/drm/drm_gem_dma_helper.h | 3 +++
4 files changed, 22 insertions(+), 14 deletions(-)
diff --git a/drivers/gpu/drm/drm_gem_dma_helper.c b/drivers/gpu/drm/drm_gem_dma_helper.c
index 1c00a71ab3c9..9722c9fc86f3 100644
--- a/drivers/gpu/drm/drm_gem_dma_helper.c
+++ b/drivers/gpu/drm/drm_gem_dma_helper.c
@@ -108,6 +108,7 @@ __drm_gem_dma_create(struct drm_device *drm, size_t size, bool private)
goto error;
}
+ dma_obj->dma_attrs |= DMA_ATTR_NO_WARN | DMA_ATTR_WRITE_COMBINE;
return dma_obj;
error:
@@ -152,9 +153,10 @@ struct drm_gem_dma_object *drm_gem_dma_create(struct drm_device *drm,
DMA_TO_DEVICE,
GFP_KERNEL | __GFP_NOWARN);
} else {
- dma_obj->vaddr = dma_alloc_wc(drm_dev_dma_dev(drm), size,
- &dma_obj->dma_addr,
- GFP_KERNEL | __GFP_NOWARN);
+ dma_obj->vaddr = dma_alloc_attrs(drm_dev_dma_dev(drm), size,
+ &dma_obj->dma_addr,
+ GFP_KERNEL | __GFP_NOWARN,
+ dma_obj->dma_attrs);
}
if (!dma_obj->vaddr) {
drm_dbg(drm, "failed to allocate buffer with size %zu\n",
@@ -242,9 +244,9 @@ void drm_gem_dma_free(struct drm_gem_dma_object *dma_obj)
dma_obj->vaddr, dma_obj->dma_addr,
DMA_TO_DEVICE);
else
- dma_free_wc(drm_dev_dma_dev(gem_obj->dev),
- dma_obj->base.size, dma_obj->vaddr,
- dma_obj->dma_addr);
+ dma_free_attrs(drm_dev_dma_dev(gem_obj->dev),
+ dma_obj->base.size, dma_obj->vaddr,
+ dma_obj->dma_addr, dma_obj->dma_attrs);
}
drm_gem_object_release(gem_obj);
@@ -435,8 +437,9 @@ struct sg_table *drm_gem_dma_get_sg_table(struct drm_gem_dma_object *dma_obj)
if (!sgt)
return ERR_PTR(-ENOMEM);
- ret = dma_get_sgtable(drm_dev_dma_dev(obj->dev), sgt, dma_obj->vaddr,
- dma_obj->dma_addr, obj->size);
+ ret = dma_get_sgtable_attrs(drm_dev_dma_dev(obj->dev), sgt,
+ dma_obj->vaddr, dma_obj->dma_addr,
+ obj->size, dma_obj->dma_attrs);
if (ret < 0)
goto out;
@@ -546,9 +549,10 @@ int drm_gem_dma_mmap(struct drm_gem_dma_object *dma_obj, struct vm_area_struct *
vma, vma->vm_end - vma->vm_start,
virt_to_page(dma_obj->vaddr));
} else {
- ret = dma_mmap_wc(drm_dev_dma_dev(dma_obj->base.dev), vma,
- dma_obj->vaddr, dma_obj->dma_addr,
- vma->vm_end - vma->vm_start);
+ ret = dma_mmap_attrs(drm_dev_dma_dev(dma_obj->base.dev), vma,
+ dma_obj->vaddr, dma_obj->dma_addr,
+ vma->vm_end - vma->vm_start,
+ dma_obj->dma_attrs);
}
if (ret)
drm_gem_vm_close(vma);
diff --git a/drivers/gpu/drm/renesas/rcar-du/rcar_du_vsp.c b/drivers/gpu/drm/renesas/rcar-du/rcar_du_vsp.c
index 94c22d2db197..a4896096e3bc 100644
--- a/drivers/gpu/drm/renesas/rcar-du/rcar_du_vsp.c
+++ b/drivers/gpu/drm/renesas/rcar-du/rcar_du_vsp.c
@@ -291,8 +291,9 @@ int rcar_du_vsp_map_fb(struct rcar_du_vsp *vsp, struct drm_framebuffer *fb,
dst = sg_next(dst);
}
} else {
- ret = dma_get_sgtable(rcdu->dev, sgt, gem->vaddr,
- gem->dma_addr, gem->base.size);
+ ret = dma_get_sgtable_attrs(rcdu->dev, sgt, gem->vaddr,
+ gem->dma_addr, gem->base.size
+ gem->dma_attrs);
if (ret)
goto fail;
}
diff --git a/drivers/gpu/drm/vc4/vc4_bo.c b/drivers/gpu/drm/vc4/vc4_bo.c
index f45ba47b4ba8..981593739a0f 100644
--- a/drivers/gpu/drm/vc4/vc4_bo.c
+++ b/drivers/gpu/drm/vc4/vc4_bo.c
@@ -304,7 +304,7 @@ static void vc4_bo_purge(struct drm_gem_object *obj)
drm_vma_node_unmap(&obj->vma_node, dev->anon_inode->i_mapping);
- dma_free_wc(dev->dev, obj->size, bo->base.vaddr, bo->base.dma_addr);
+ dma_free_attrs(dev->dev, obj->size, bo->base.vaddr, bo->base.dma_addr, bo->base.dma_attrs);
bo->base.vaddr = NULL;
bo->madv = __VC4_MADV_PURGED;
}
diff --git a/include/drm/drm_gem_dma_helper.h b/include/drm/drm_gem_dma_helper.h
index f2678e7ecb98..e815ff121e23 100644
--- a/include/drm/drm_gem_dma_helper.h
+++ b/include/drm/drm_gem_dma_helper.h
@@ -16,6 +16,8 @@ struct drm_mode_create_dumb;
* more than one entry but they are guaranteed to have contiguous
* DMA addresses.
* @vaddr: kernel virtual address of the backing memory
+ * @dma_attrs: DMA attributes used when allocating backing memory.
+ * Only applies to coherent memory.
* @map_noncoherent: if true, the GEM object is backed by non-coherent memory
*/
struct drm_gem_dma_object {
@@ -25,6 +27,7 @@ struct drm_gem_dma_object {
/* For objects with DMA memory allocated by GEM DMA */
void *vaddr;
+ unsigned long dma_attrs;
bool map_noncoherent;
};
--
2.53.0.1018.g2bb0e51243-googHi Chen-Yu,
kernel test robot noticed the following build errors:
[auto build test ERROR on drm-misc/drm-misc-next]
[also build test ERROR on next-20260327]
[cannot apply to sunxi/sunxi/for-next linus/master v7.0-rc5]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Chen-Yu-Tsai/drm-Introduce-DRM_MODE_DUMB_KERNEL_MAP-flag/20260328-141115
base: https://gitlab.freedesktop.org/drm/misc/kernel.git drm-misc-next
patch link: https://lore.kernel.org/r/20260326100248.1171828-3-wenst%40chromium.org
patch subject: [PATCH v3 2/3] drm/gem-dma: Use the dma_*_attr API variant
config: arm64-allmodconfig (https://download.01.org/0day-ci/archive/20260329/202603290350.pIgD9ufQ-lkp@intel.com/config)
compiler: clang version 19.1.7 (https://github.com/llvm/llvm-project cd708029e0b2869e80abe31ddb175f7c35361f90)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260329/202603290350.pIgD9ufQ-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202603290350.pIgD9ufQ-lkp@intel.com/
All errors (new ones prefixed by >>):
>> drivers/gpu/drm/renesas/rcar-du/rcar_du_vsp.c:297:11: error: expected ')'
297 | gem->dma_attrs);
| ^
drivers/gpu/drm/renesas/rcar-du/rcar_du_vsp.c:295:31: note: to match this '('
295 | ret = dma_get_sgtable_attrs(rcdu->dev, sgt, gem->vaddr,
| ^
1 error generated.
vim +297 drivers/gpu/drm/renesas/rcar-du/rcar_du_vsp.c
258
259 int rcar_du_vsp_map_fb(struct rcar_du_vsp *vsp, struct drm_framebuffer *fb,
260 struct sg_table sg_tables[3])
261 {
262 struct rcar_du_device *rcdu = vsp->dev;
263 unsigned int i, j;
264 int ret;
265
266 for (i = 0; i < fb->format->num_planes; ++i) {
267 struct drm_gem_dma_object *gem = drm_fb_dma_get_gem_obj(fb, i);
268 struct sg_table *sgt = &sg_tables[i];
269
270 if (gem->sgt) {
271 struct scatterlist *src;
272 struct scatterlist *dst;
273
274 /*
275 * If the GEM buffer has a scatter gather table, it has
276 * been imported from a dma-buf and has no physical
277 * address as it might not be physically contiguous.
278 * Copy the original scatter gather table to map it to
279 * the VSP.
280 */
281 ret = sg_alloc_table(sgt, gem->sgt->orig_nents,
282 GFP_KERNEL);
283 if (ret)
284 goto fail;
285
286 src = gem->sgt->sgl;
287 dst = sgt->sgl;
288 for (j = 0; j < gem->sgt->orig_nents; ++j) {
289 sg_set_page(dst, sg_page(src), src->length,
290 src->offset);
291 src = sg_next(src);
292 dst = sg_next(dst);
293 }
294 } else {
295 ret = dma_get_sgtable_attrs(rcdu->dev, sgt, gem->vaddr,
296 gem->dma_addr, gem->base.size
> 297 gem->dma_attrs);
298 if (ret)
299 goto fail;
300 }
301
302 ret = vsp1_du_map_sg(vsp->vsp, sgt);
303 if (ret) {
304 sg_free_table(sgt);
305 goto fail;
306 }
307 }
308
309 return 0;
310
311 fail:
312 while (i--) {
313 struct sg_table *sgt = &sg_tables[i];
314
315 vsp1_du_unmap_sg(vsp->vsp, sgt);
316 sg_free_table(sgt);
317 }
318
319 return ret;
320 }
321
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
Hi Chen-Yu,
kernel test robot noticed the following build errors:
[auto build test ERROR on drm-misc/drm-misc-next]
[also build test ERROR on next-20260327]
[cannot apply to sunxi/sunxi/for-next linus/master v7.0-rc5]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Chen-Yu-Tsai/drm-Introduce-DRM_MODE_DUMB_KERNEL_MAP-flag/20260328-141115
base: https://gitlab.freedesktop.org/drm/misc/kernel.git drm-misc-next
patch link: https://lore.kernel.org/r/20260326100248.1171828-3-wenst%40chromium.org
patch subject: [PATCH v3 2/3] drm/gem-dma: Use the dma_*_attr API variant
config: arm64-defconfig (https://download.01.org/0day-ci/archive/20260328/202603282331.VKpi5ANh-lkp@intel.com/config)
compiler: aarch64-linux-gcc (GCC) 15.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260328/202603282331.VKpi5ANh-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202603282331.VKpi5ANh-lkp@intel.com/
All errors (new ones prefixed by >>):
drivers/gpu/drm/renesas/rcar-du/rcar_du_vsp.c: In function 'rcar_du_vsp_map_fb':
>> drivers/gpu/drm/renesas/rcar-du/rcar_du_vsp.c:296:82: error: expected ')' before 'gem'
296 | gem->dma_addr, gem->base.size
| ^
| )
297 | gem->dma_attrs);
| ~~~
drivers/gpu/drm/renesas/rcar-du/rcar_du_vsp.c:295:52: note: to match this '('
295 | ret = dma_get_sgtable_attrs(rcdu->dev, sgt, gem->vaddr,
| ^
>> drivers/gpu/drm/renesas/rcar-du/rcar_du_vsp.c:295:31: error: too few arguments to function 'dma_get_sgtable_attrs'; expected 6, have 5
295 | ret = dma_get_sgtable_attrs(rcdu->dev, sgt, gem->vaddr,
| ^~~~~~~~~~~~~~~~~~~~~
In file included from include/linux/dma-buf.h:21,
from include/drm/drm_gem.h:38,
from include/drm/drm_gem_dma_helper.h:7,
from drivers/gpu/drm/renesas/rcar-du/rcar_du_vsp.c:18:
include/linux/dma-mapping.h:172:5: note: declared here
172 | int dma_get_sgtable_attrs(struct device *dev, struct sg_table *sgt,
| ^~~~~~~~~~~~~~~~~~~~~
vim +296 drivers/gpu/drm/renesas/rcar-du/rcar_du_vsp.c
258
259 int rcar_du_vsp_map_fb(struct rcar_du_vsp *vsp, struct drm_framebuffer *fb,
260 struct sg_table sg_tables[3])
261 {
262 struct rcar_du_device *rcdu = vsp->dev;
263 unsigned int i, j;
264 int ret;
265
266 for (i = 0; i < fb->format->num_planes; ++i) {
267 struct drm_gem_dma_object *gem = drm_fb_dma_get_gem_obj(fb, i);
268 struct sg_table *sgt = &sg_tables[i];
269
270 if (gem->sgt) {
271 struct scatterlist *src;
272 struct scatterlist *dst;
273
274 /*
275 * If the GEM buffer has a scatter gather table, it has
276 * been imported from a dma-buf and has no physical
277 * address as it might not be physically contiguous.
278 * Copy the original scatter gather table to map it to
279 * the VSP.
280 */
281 ret = sg_alloc_table(sgt, gem->sgt->orig_nents,
282 GFP_KERNEL);
283 if (ret)
284 goto fail;
285
286 src = gem->sgt->sgl;
287 dst = sgt->sgl;
288 for (j = 0; j < gem->sgt->orig_nents; ++j) {
289 sg_set_page(dst, sg_page(src), src->length,
290 src->offset);
291 src = sg_next(src);
292 dst = sg_next(dst);
293 }
294 } else {
> 295 ret = dma_get_sgtable_attrs(rcdu->dev, sgt, gem->vaddr,
> 296 gem->dma_addr, gem->base.size
297 gem->dma_attrs);
298 if (ret)
299 goto fail;
300 }
301
302 ret = vsp1_du_map_sg(vsp->vsp, sgt);
303 if (ret) {
304 sg_free_table(sgt);
305 goto fail;
306 }
307 }
308
309 return 0;
310
311 fail:
312 while (i--) {
313 struct sg_table *sgt = &sg_tables[i];
314
315 vsp1_du_unmap_sg(vsp->vsp, sgt);
316 sg_free_table(sgt);
317 }
318
319 return ret;
320 }
321
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
On Thu, Mar 26, 2026 at 6:03 PM Chen-Yu Tsai <wenst@chromium.org> wrote:
>
> From: Rob Herring <robh@kernel.org>
>
> In preparation to allow DRM DMA users to adjust the DMA_ATTR_* flags,
> convert the DMA helper code to use the dma_*_attr APIs instead of the
> dma_*_wc variants.
>
> Only the DMA_ATTR_WRITE_COMBINE and DMA_ATTR_NO_WARN attributes are set
> in this commit, so there's no functional change.
>
> Update rcar_du_vsp_map_fb() to use dma_get_sgtable_attrs() instead of
> dma_get_sgtable().
>
> Also change the dma_free_wc() call in vc4_bo_purge() in the vc4 driver
> to use dma_free_attrs() to match. vc4_bo is a sub-class of
> drm_gem_dma_object.
>
> Sub-classes of |struct drm_gem_dma_object| can also set additional
> DMA_ATTR_* flags if they choose so. For example a sub-class could
> set DMA_ATTR_FORCE_CONTIGUOUS in certain cases.
>
> Signed-off-by: Rob Herring <robh@kernel.org>
> [wenst@chromium.org: Rebase onto renamed DMA helpers]
> [wenst@chromium.org: Make vc4_bo_purge() use matching dma_free_attrs()]
> [wenst@chromium.org: Make rcar_du_vsp_map_fb() use dma_get_sgtable_attrs()]
> [wenst@chromium.org: Expand commit message to mention that sub-classes
> can set extra DMA_ATTR_* flags]
> Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
>
> ---
> Changes since v2:
> - rcar-du: Change dma_get_sgtable() to dma_get_sgtable_attrs()
>
> Changes since v1:
> - Rebased onto renamed DMA helpers
> - Made vc4_bo_purge() use matching dma_free_attrs()
> - Expanded commit message to mention that sub-classes can set extra
> DMA_ATTR_* flags
> ---
> drivers/gpu/drm/drm_gem_dma_helper.c | 26 +++++++++++--------
> drivers/gpu/drm/renesas/rcar-du/rcar_du_vsp.c | 5 ++--
> drivers/gpu/drm/vc4/vc4_bo.c | 2 +-
> include/drm/drm_gem_dma_helper.h | 3 +++
> 4 files changed, 22 insertions(+), 14 deletions(-)
[...]
> diff --git a/drivers/gpu/drm/renesas/rcar-du/rcar_du_vsp.c b/drivers/gpu/drm/renesas/rcar-du/rcar_du_vsp.c
> index 94c22d2db197..a4896096e3bc 100644
> --- a/drivers/gpu/drm/renesas/rcar-du/rcar_du_vsp.c
> +++ b/drivers/gpu/drm/renesas/rcar-du/rcar_du_vsp.c
> @@ -291,8 +291,9 @@ int rcar_du_vsp_map_fb(struct rcar_du_vsp *vsp, struct drm_framebuffer *fb,
> dst = sg_next(dst);
> }
> } else {
> - ret = dma_get_sgtable(rcdu->dev, sgt, gem->vaddr,
> - gem->dma_addr, gem->base.size);
> + ret = dma_get_sgtable_attrs(rcdu->dev, sgt, gem->vaddr,
> + gem->dma_addr, gem->base.size
> + gem->dma_attrs);
This doesn't compile. Sorry for the noise.
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