[v4,23/25] drm/xe: Compute dumb-buffer sizes with drm_mode_size_dumb()

Commit Message

Thomas Zimmermann March 11, 2025, 3:47 p.m. UTC

Call drm_mode_size_dumb() to compute dumb-buffer scanline pitch
and buffer size. Align the pitch to a multiple of 8. Align the
buffer size according to hardware requirements.

Xe's internal calculation allowed for 64-bit wide buffer sizes, but
the ioctl's internal checks always verified against 32-bit wide limits.
Hance, it is safe to limit the driver code to 32-bit calculations as
well.

v3:
- mention 32-bit calculation in commit description (Matthew)

Signed-off-by: Thomas Zimmermann <[e-mail]>
Reviewed-by: Matthew Auld <[e-mail]>
Cc: Lucas De Marchi <[e-mail]>
Cc: "Thomas Hellström" <[e-mail]>
Cc: Rodrigo Vivi <[e-mail]>
---
 drivers/gpu/drm/xe/xe_bo.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

Patch

diff --git a/drivers/gpu/drm/xe/xe_bo.c b/drivers/gpu/drm/xe/xe_bo.c
index 64f9c936eea0..471aab61176e 100644
--- a/drivers/gpu/drm/xe/xe_bo.c
+++ b/drivers/gpu/drm/xe/xe_bo.c
@@ -9,6 +9,7 @@ 
 #include <linux/nospec.h>
 
 #include <drm/drm_drv.h>
+#include <drm/drm_dumb_buffers.h>
 #include <drm/drm_gem_ttm_helper.h>
 #include <drm/drm_managed.h>
 #include <drm/ttm/ttm_backup.h>
@@ -2910,14 +2911,13 @@  int xe_bo_dumb_create(struct drm_file *file_priv,
 	struct xe_device *xe = to_xe_device(dev);
 	struct xe_bo *bo;
 	uint32_t handle;
-	int cpp = DIV_ROUND_UP(args->bpp, 8);
 	int err;
 	u32 page_size = max_t(u32, PAGE_SIZE,
 		xe->info.vram_flags & XE_VRAM_FLAGS_NEED64K ? SZ_64K : SZ_4K);
 
-	args->pitch = ALIGN(args->width * cpp, 64);
-	args->size = ALIGN(mul_u32_u32(args->pitch, args->height),
-			   page_size);
+	err = drm_mode_size_dumb(dev, args, SZ_64, page_size);
+	if (err)
+		return err;
 
 	bo = xe_bo_create_user(xe, NULL, NULL, args->size,
 			       DRM_XE_GEM_CPU_CACHING_WC,