[PATCH v4 07/14] drm/panic: Return from screen_user if display is too small

[Thomas Zimmermann]

Return an error if the display is too small to display at least a
single character. If the panic handler cannot display any message
it does at least not destroy the current output, which might help
with identifying the problem.

v4:
- also check font height against scanout buffer (Jocelyn)

Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe at redhat.com>
---
 drivers/gpu/drm/drm_panic.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_panic.c b/drivers/gpu/drm/drm_panic.c
index f597ef04c5bc..b1cd5e5865a0 100644
--- a/drivers/gpu/drm/drm_panic.c
+++ b/drivers/gpu/drm/drm_panic.c
@@ -486,7 +486,7 @@ static int draw_panic_screen_user(struct drm_scanout_buffer *sb, u32 fg_color, u
 	struct drm_rect r_screen, r_logo, r_msg;
 	unsigned int msg_width, msg_height;
 
-	if (!font)
+	if (!font || font->width > sb->width || font->height > sb->height)
 		return -EINVAL;
 
 	fg_color = drm_draw_color_from_xrgb8888(fg_color, sb->format->format);
@@ -560,7 +560,7 @@ static int draw_panic_screen_kmsg(struct drm_scanout_buffer *sb, u32 fg_color, u
 	struct drm_panic_line line;
 	int yoffset;
 
-	if (!font || font->width > sb->width)
+	if (!font || font->width > sb->width || font->height > sb->height)
 		return -EINVAL;
 
 	fg_color = drm_draw_color_from_xrgb8888(fg_color, sb->format->format);
-- 
2.55.0