diff mbox series

[v2,1/4] drm/prime: Limit scatter list size with dedicated DMA device

Message ID 20260311094929.3393338-2-wenst@chromium.org (mailing list archive)
State New
Headers
Series drm/gem-dma: Support dedicated DMA device for allocation |

Commit Message

Chen-Yu Tsai March 11, 2026, 9:49 a.m. UTC 
If a dedicated DMA device is specified for the DRM device, then the
scatter list size limit should pertain to the DMA device.

Use the dedicated DMA device, if given, to limit the scatter list size.
This only applies to drivers that have called drm_dev_set_dma_dev() and
are using drm_prime_pages_to_sg() either directly or through the SHMEM
helpers. At the time of this writing, the former case only includes the
Rockchip DRM driver, while the latter case includes the gud, udl, and
the tiny appletbdrm and gm12u320 drivers.

Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
---
 drivers/gpu/drm/drm_prime.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

AngeloGioacchino Del Regno March 11, 2026, 2:40 p.m. UTC | #1 
Il 11/03/26 10:49, Chen-Yu Tsai ha scritto:
> If a dedicated DMA device is specified for the DRM device, then the
> scatter list size limit should pertain to the DMA device.
> 
> Use the dedicated DMA device, if given, to limit the scatter list size.
> This only applies to drivers that have called drm_dev_set_dma_dev() and
> are using drm_prime_pages_to_sg() either directly or through the SHMEM
> helpers. At the time of this writing, the former case only includes the
> Rockchip DRM driver, while the latter case includes the gud, udl, and
> the tiny appletbdrm and gm12u320 drivers.
> 
> Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
> Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
diff mbox series

Patch

diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index 51fdb06d3e9f..9b44c78cd77f 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -859,7 +859,7 @@  struct sg_table *drm_prime_pages_to_sg(struct drm_device *dev,
 		return ERR_PTR(-ENOMEM);
 
 	if (dev)
-		max_segment = dma_max_mapping_size(dev->dev);
+		max_segment = dma_max_mapping_size(drm_dev_dma_dev(dev));
 	if (max_segment == 0)
 		max_segment = UINT_MAX;
 	err = sg_alloc_table_from_pages_segment(sg, pages, nr_pages, 0,