[PATCH v3 08/14] drm/panic: Retry in dispatch function if panic output fails

[Thomas Zimmermann <tzimmermann@suse.de>]

On failed output of QR codes and kmsg buffers, fall back to a user
message. QR-code output already did this internally, but now formally
support it in drm_panic_dispatch(). Streamlines the existing logic.

With the implicit fallback removed from QR-code support, the tests
cases fail for thr smallest output size (300x200). This is because the
QR code requires a minimal output size. Increase the size to 494x494,
which is the minimum supported size for QR output.

v3:
- update outdated commit description (Sashiko)
v2:
- fix minimum test size (Sashiko)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
---
 drivers/gpu/drm/drm_panic.c            | 24 ++++++++++++------------
 drivers/gpu/drm/tests/drm_panic_test.c |  2 +-
 2 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/drm_panic.c b/drivers/gpu/drm/drm_panic.c
index c317afc76669..690e96e8f1f9 100644
--- a/drivers/gpu/drm/drm_panic.c
+++ b/drivers/gpu/drm/drm_panic.c
@@ -740,9 +740,9 @@ static int drm_panic_get_qr_code(u8 **qr_image, unsigned int qr_version)
 /*
  * Draw the panic message at the center of the screen, with a QR Code
  */
-static int _draw_panic_screen_qr_code(struct drm_scanout_buffer *sb,
-				      u32 fg_color, u32 bg_color,
-				      unsigned int qr_version)
+static int draw_panic_screen_qr_code(struct drm_scanout_buffer *sb,
+				     u32 fg_color, u32 bg_color,
+				     unsigned int qr_version)
 {
 	const struct font_desc *font = get_default_font(sb->width, sb->height, NULL, NULL);
 	struct drm_rect r_screen, r_logo, r_msg, r_qr, r_qr_canvas;
@@ -812,15 +812,6 @@ static int _draw_panic_screen_qr_code(struct drm_scanout_buffer *sb,
 	drm_panic_blit(sb, &r_qr, qr_image, qr_pitch, scale, fg_color);
 	return 0;
 }
-
-static int draw_panic_screen_qr_code(struct drm_scanout_buffer *sb,
-				     u32 fg_color, u32 bg_color,
-				     unsigned int qr_version)
-{
-	if (_draw_panic_screen_qr_code(sb, fg_color, bg_color, qr_version))
-		return draw_panic_screen_user(sb, fg_color, bg_color);
-	return 0;
-}
 #else
 static void drm_panic_qr_init(void) {};
 static void drm_panic_qr_exit(void) {};
@@ -895,13 +886,22 @@ static int draw_panic_dispatch(struct drm_scanout_buffer *sb, enum drm_panic_typ
 {
 	int ret;
 
+retry:
 	switch (panic_type) {
 	case DRM_PANIC_TYPE_KMSG:
 		ret = draw_panic_screen_kmsg(sb, fg_color, bg_color);
+		if (ret) {
+			panic_type = DRM_PANIC_TYPE_USER;
+			goto retry;
+		}
 		break;
 #if IS_ENABLED(CONFIG_DRM_PANIC_SCREEN_QR_CODE)
 	case DRM_PANIC_TYPE_QR:
 		ret = draw_panic_screen_qr_code(sb, fg_color, bg_color, qr_version);
+		if (ret) {
+			panic_type = DRM_PANIC_TYPE_USER;
+			goto retry;
+		}
 		break;
 #endif
 	case DRM_PANIC_TYPE_USER:
diff --git a/drivers/gpu/drm/tests/drm_panic_test.c b/drivers/gpu/drm/tests/drm_panic_test.c
index 196496238d23..55d77bc203df 100644
--- a/drivers/gpu/drm/tests/drm_panic_test.c
+++ b/drivers/gpu/drm/tests/drm_panic_test.c
@@ -32,7 +32,7 @@ struct drm_test_mode {
  */
 #define DRM_TEST_MODE_LIST(func) \
 	DRM_PANIC_TEST_MODE(1024, 768, DRM_FORMAT_XRGB8888, func) \
-	DRM_PANIC_TEST_MODE(300, 200, DRM_FORMAT_XRGB8888, func) \
+	DRM_PANIC_TEST_MODE(494, 494, DRM_FORMAT_XRGB8888, func) \
 	DRM_PANIC_TEST_MODE(1920, 1080, DRM_FORMAT_XRGB8888, func) \
 	DRM_PANIC_TEST_MODE(1024, 768, DRM_FORMAT_RGB565, func) \
 	DRM_PANIC_TEST_MODE(1024, 768, DRM_FORMAT_RGB888, func) \
-- 
2.55.0