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

Chen-Yu Tsai posted 4 patches 3 weeks, 6 days ago
[PATCH v2 1/4] drm/prime: Limit scatter list size with dedicated DMA device
Posted by Chen-Yu Tsai 3 weeks, 6 days ago
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(-)

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,
-- 
2.53.0.473.g4a7958ca14-goog
Re: [PATCH v2 1/4] drm/prime: Limit scatter list size with dedicated DMA device
Posted by AngeloGioacchino Del Regno 3 weeks, 6 days ago
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>