panic: Pass colors to draw_panic_dispatch()

Jocelyn Falempe Thu, 20 Aug 2026 14:05:17 -0700

On 18/08/2026 14:28, Thomas Zimmermann wrote:

Set the panic-screen colors in draw_panic_plane() as a single point
of truth. Pass the values into the individual drawing functions.


In the test cases, replace the Kconfig-defined colors with white and
black. Allows for removal of the tests' limitations and dependency on
the exact values. All tests now always verify the generated output.

Hardcoding the test colors will later also allow for building the
test case without having DRM panic handling enabled.

Thanks, that makes sense, I should've think about it, as this colors wasa bit painful when writing the KUnit tests.


Reviewed-by: Jocelyn Falempe <[email protected]>


Signed-off-by: Thomas Zimmermann <[email protected]>
---
  drivers/gpu/drm/drm_panic.c            | 54 +++++++++++++++-----------
  drivers/gpu/drm/tests/drm_panic_test.c | 26 +++++++++----
  2 files changed, 49 insertions(+), 31 deletions(-)

diff --git a/drivers/gpu/drm/drm_panic.c b/drivers/gpu/drm/drm_panic.c
index 594235661710..ede620b27515 100644
--- a/drivers/gpu/drm/drm_panic.c
+++ b/drivers/gpu/drm/drm_panic.c
@@ -478,12 +478,8 @@ static void drm_panic_logo_draw(struct drm_scanout_buffer 
*sb, struct drm_rect *
                                   fg_color);
  }

-static int draw_panic_screen_user(struct drm_scanout_buffer *sb)

+static int draw_panic_screen_user(struct drm_scanout_buffer *sb, u32 fg_color, 
u32 bg_color)
  {
-       u32 fg_color = 
drm_draw_color_from_xrgb8888(CONFIG_DRM_PANIC_FOREGROUND_COLOR,
-                                                   sb->format->format);
-       u32 bg_color = 
drm_draw_color_from_xrgb8888(CONFIG_DRM_PANIC_BACKGROUND_COLOR,
-                                                   sb->format->format);
        const struct font_desc *font = get_default_font(sb->width, sb->height, 
NULL, NULL);
        struct drm_rect r_screen, r_logo, r_msg;
        unsigned int msg_width, msg_height;
@@ -491,6 +487,9 @@ static int draw_panic_screen_user(struct drm_scanout_buffer 
*sb)
        if (!font)
                return -EINVAL;

+ fg_color = drm_draw_color_from_xrgb8888(fg_color, sb->format->format);

+       bg_color = drm_draw_color_from_xrgb8888(bg_color, sb->format->format);
+
        r_screen = DRM_RECT_INIT(0, 0, sb->width, sb->height);
        drm_panic_logo_rect(&r_logo, font);

@@ -549,12 +548,8 @@ static int draw_line_with_wrap(struct drm_scanout_buffer *sb, const struct font_

   * Draw the kmsg buffer to the screen, starting from the youngest message at 
the bottom,
   * and going up until reaching the top of the screen.
   */
-static int draw_panic_screen_kmsg(struct drm_scanout_buffer *sb)
+static int draw_panic_screen_kmsg(struct drm_scanout_buffer *sb, u32 fg_color, 
u32 bg_color)
  {
-       u32 fg_color = 
drm_draw_color_from_xrgb8888(CONFIG_DRM_PANIC_FOREGROUND_COLOR,
-                                                   sb->format->format);
-       u32 bg_color = 
drm_draw_color_from_xrgb8888(CONFIG_DRM_PANIC_BACKGROUND_COLOR,
-                                                   sb->format->format);
        const struct font_desc *font = get_default_font(sb->width, sb->height, 
NULL, NULL);
        struct drm_rect r_screen = DRM_RECT_INIT(0, 0, sb->width, sb->height);
        struct kmsg_dump_iter iter;
@@ -566,6 +561,9 @@ static int draw_panic_screen_kmsg(struct drm_scanout_buffer 
*sb)
        if (!font || font->width > sb->width)
                return -EINVAL;

+ fg_color = drm_draw_color_from_xrgb8888(fg_color, sb->format->format);

+       bg_color = drm_draw_color_from_xrgb8888(bg_color, sb->format->format);
+
        yoffset = sb->height - font->height - (sb->height % font->height) / 2;

/* Fill with the background color, and draw text on top */

@@ -748,12 +746,9 @@ static int drm_panic_get_qr_code(u8 **qr_image)
  /*
   * 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)
+static int _draw_panic_screen_qr_code(struct drm_scanout_buffer *sb,
+                                     u32 fg_color, u32 bg_color)
  {
-       u32 fg_color = 
drm_draw_color_from_xrgb8888(CONFIG_DRM_PANIC_FOREGROUND_COLOR,
-                                                   sb->format->format);
-       u32 bg_color = 
drm_draw_color_from_xrgb8888(CONFIG_DRM_PANIC_BACKGROUND_COLOR,
-                                                   sb->format->format);
        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;
        unsigned int max_qr_size, scale;
@@ -766,6 +761,9 @@ static int _draw_panic_screen_qr_code(struct 
drm_scanout_buffer *sb)
        if (!font)
                return -EINVAL;

+ fg_color = drm_draw_color_from_xrgb8888(fg_color, sb->format->format);

+       bg_color = drm_draw_color_from_xrgb8888(bg_color, sb->format->format);
+
        r_screen = DRM_RECT_INIT(0, 0, sb->width, sb->height);

drm_panic_logo_rect(&r_logo, font);

@@ -818,10 +816,10 @@ static int _draw_panic_screen_qr_code(struct 
drm_scanout_buffer *sb)
        return 0;
  }

-static int draw_panic_screen_qr_code(struct drm_scanout_buffer *sb)

+static int draw_panic_screen_qr_code(struct drm_scanout_buffer *sb, u32 
fg_color, u32 bg_color)
  {
-       if (_draw_panic_screen_qr_code(sb))
-               draw_panic_screen_user(sb);
+       if (_draw_panic_screen_qr_code(sb, fg_color, bg_color))
+               draw_panic_screen_user(sb, fg_color, bg_color);
        return 0;
  }
  #else
@@ -893,22 +891,22 @@ static bool drm_panic_is_format_supported(const struct 
drm_format_info *format)
        return drm_draw_can_convert_from_xrgb8888(format->format);
  }

-static int draw_panic_dispatch(struct drm_scanout_buffer *sb)

+static int draw_panic_dispatch(struct drm_scanout_buffer *sb, u32 fg_color, 
u32 bg_color)
  {
        int ret;

switch (drm_panic_type) {

        case DRM_PANIC_TYPE_KMSG:
-               ret = draw_panic_screen_kmsg(sb);
+               ret = draw_panic_screen_kmsg(sb, fg_color, bg_color);
                break;
  #if IS_ENABLED(CONFIG_DRM_PANIC_SCREEN_QR_CODE)
        case DRM_PANIC_TYPE_QR:
-               ret = draw_panic_screen_qr_code(sb);
+               ret = draw_panic_screen_qr_code(sb, fg_color, bg_color);
                break;
  #endif
        case DRM_PANIC_TYPE_USER:
        default:
-               ret = draw_panic_screen_user(sb);
+               ret = draw_panic_screen_user(sb, fg_color, bg_color);
        }

return ret;

@@ -943,6 +941,16 @@ static void draw_panic_plane(struct drm_plane *plane, 
const char *description)
        struct drm_scanout_buffer sb = { };
        int ret;
        unsigned long flags;
+#if defined(CONFIG_DRM_PANIC_FOREGROUND_COLOR)
+       u32 fg_color = CONFIG_DRM_PANIC_FOREGROUND_COLOR;
+#else
+       u32 fg_color = 0x00ffffff;
+#endif
+#if defined(CONFIG_DRM_PANIC_BACKGROUND_COLOR)
+       u32 bg_color = CONFIG_DRM_PANIC_BACKGROUND_COLOR;
+#else
+       u32 bg_color = 0x00000000;
+#endif

if (!drm_panic_trylock(plane->dev, flags))

                return;
@@ -958,7 +966,7 @@ static void draw_panic_plane(struct drm_plane *plane, const 
char *description)

drm_panic_set_description(description);- ret = draw_panic_dispatch(&sb);

+       ret = draw_panic_dispatch(&sb, fg_color, bg_color);
        if (!ret) {
                /*
                 * Only flush if we have a panic screen to display. Otherwise
diff --git a/drivers/gpu/drm/tests/drm_panic_test.c 
b/drivers/gpu/drm/tests/drm_panic_test.c
index fdd77b0cc54c..969a096ec840 100644
--- a/drivers/gpu/drm/tests/drm_panic_test.c
+++ b/drivers/gpu/drm/tests/drm_panic_test.c
@@ -14,17 +14,10 @@
  #include <linux/units.h>
  #include <linux/vmalloc.h>

-/* Check the framebuffer color only if the panic colors are the default */

-#if (CONFIG_DRM_PANIC_BACKGROUND_COLOR == 0 && \
-       CONFIG_DRM_PANIC_FOREGROUND_COLOR == 0xffffff)
-
  static void drm_panic_check_color_byte(struct kunit *test, u8 b)
  {
        KUNIT_EXPECT_TRUE(test, (b == 0 || b == 0xff));
  }
-#else
-static void drm_panic_check_color_byte(struct kunit *test, u8 b) {}
-#endif

struct drm_test_mode {

        const int width;
@@ -48,10 +41,27 @@ struct drm_test_mode {
        .width = w, \
        .height = h, \
        .format = f, \
-       .draw_screen = draw_panic_screen_##name, \
+       .draw_screen = draw_panic_screen_ ## name ## _default, \
        .fname = #name, \
        }, \

+static int draw_panic_screen_user_default(struct drm_scanout_buffer *sb)

+{
+       return draw_panic_screen_user(sb, 0x00ffffff, 0x00000000);
+}
+
+static int draw_panic_screen_kmsg_default(struct drm_scanout_buffer *sb)
+{
+       return draw_panic_screen_kmsg(sb, 0x00ffffff, 0x00000000);
+}
+
+#if IS_ENABLED(CONFIG_DRM_PANIC_SCREEN_QR_CODE)
+static int draw_panic_screen_qr_code_default(struct drm_scanout_buffer *sb)
+{
+       return draw_panic_screen_qr_code(sb, 0x00ffffff, 0x00000000);
+}
+#endif
+
  static const struct drm_test_mode drm_test_modes_cases[] = {
        DRM_TEST_MODE_LIST(user)
        DRM_TEST_MODE_LIST(kmsg)

Re: [PATCH 05/12] drm/panic: Pass colors to draw_panic_dispatch()

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