Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
drm/ast: Validate display modes against framebuffer and format limits
Reimplement ast_mode_config_mode_valid() with DRM format helpers and
ast's helpers for framebuffer size calculation. Replaces ast's open-
coded assumptions on bpp and page-alignments.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://lore.kernel.org/r/20250324094520.192974-4-tzimmermann@suse.de
+13
-7
+13
-7
drivers/gpu/drm/ast/ast_mode.c
+13
-7
drivers/gpu/drm/ast/ast_mode.c
···
51
51
52
52
#define AST_LUT_SIZE 256
53
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+
#define AST_PRIMARY_PLANE_MAX_OFFSET (BIT(16) - 1)
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+
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static unsigned long ast_fb_vram_offset(void)
55
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{
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return 0; // with shmem, the primary plane is always at offset 0
···
962
960
static enum drm_mode_status ast_mode_config_mode_valid(struct drm_device *dev,
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const struct drm_display_mode *mode)
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{
965
-
static const unsigned long max_bpp = 4; /* DRM_FORMAT_XRGB8888 */
963
+
const struct drm_format_info *info = drm_format_info(DRM_FORMAT_XRGB8888);
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struct ast_device *ast = to_ast_device(dev);
967
-
unsigned long fbsize, fbpages, max_fbpages;
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+
unsigned long max_fb_size = ast_fb_vram_size(ast);
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+
u64 pitch;
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967
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-
max_fbpages = ast_fb_vram_size(ast) >> PAGE_SHIFT;
968
+
if (drm_WARN_ON_ONCE(dev, !info))
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+
return MODE_ERROR; /* driver bug */
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971
-
fbsize = mode->hdisplay * mode->vdisplay * max_bpp;
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-
fbpages = DIV_ROUND_UP(fbsize, PAGE_SIZE);
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-
974
-
if (fbpages > max_fbpages)
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+
pitch = drm_format_info_min_pitch(info, 0, mode->hdisplay);
972
+
if (!pitch)
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+
return MODE_BAD_WIDTH;
974
+
if (pitch > AST_PRIMARY_PLANE_MAX_OFFSET)
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+
return MODE_BAD_WIDTH; /* maximum programmable pitch */
976
+
if (pitch > max_fb_size / mode->vdisplay)
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return MODE_MEM;
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return MODE_OK;