Hi
Am 24.10.25 um 13:53 schrieb Tvrtko Ursulin:
On 24/10/2025 12:04, Jocelyn Falempe wrote:
On a lenovo se100 server, when using i915 GPU for rendering, and the
ast driver for display, the graphic output is corrupted, and almost
unusable.
Adding a clflush call in the vmap function fixes this issue
completely.
AST is importing i915 allocated buffer in this use case, or how
exactly is the relationship?
Wondering if some path is not calling dma_buf_begin/end_cpu_access().
Yes, ast doesn't call begin/end_cpu_access in [1].
Jocelyn, if that fixes the issue, feel free to send me a patch for review.
[1]
https://elixir.bootlin.com/linux/v6.17.4/source/drivers/gpu/drm/ast/ast_mode.c
Best regards
Thomas
Regards,
Tvrtko
Signed-off-by: Jocelyn Falempe <[email protected]>
---
drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
index f4f1c979d1b9..f6a8c1cbe4d1 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
@@ -77,6 +77,7 @@ static int i915_gem_dmabuf_vmap(struct dma_buf
*dma_buf,
return PTR_ERR(vaddr);
iosys_map_set_vaddr(map, vaddr);
+ drm_clflush_virt_range(vaddr, dma_buf->size);
return 0;
}
base-commit: 0790925dadad0997580df6e32cdccd54316807f2
--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)
