Re: [PATCH v2 7/7] drm/panic: Add support for drawing a monochrome graphical logo

[Jocelyn Falempe]

On 13/06/2024 21:18, Geert Uytterhoeven wrote:
Re-use the existing support for boot-up logos to draw a monochrome
graphical logo in the DRM panic handler.  When no suitable graphical
logo is available, the code falls back to the ASCII art penguin logo.

Note that all graphical boot-up logos are freed during late kernel
initialization, hence a copy must be made for later use.

Would it be possible to have the logo not in the __init section if 
DRM_PANIC is set ?

The patch looks good to me anyway.

Reviewed-by: Jocelyn Falempe <jfale...@redhat.com>


Signed-off-by: Geert Uytterhoeven <geert+rene...@glider.be>
---
v2:
   - Rebased,
   - Inline trivial draw_logo_mono().
---
  drivers/gpu/drm/drm_panic.c | 65 +++++++++++++++++++++++++++++++++----
  drivers/video/logo/Kconfig  |  2 ++
  2 files changed, 60 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/drm_panic.c b/drivers/gpu/drm/drm_panic.c
index f7e22b69bb25d3be..af30f243b2802ad7 100644
--- a/drivers/gpu/drm/drm_panic.c
+++ b/drivers/gpu/drm/drm_panic.c
@@ -7,11 +7,15 @@
   */
  
  #include <linux/font.h>
+#include <linux/init.h>
  #include <linux/iosys-map.h>
  #include <linux/kdebug.h>
  #include <linux/kmsg_dump.h>
+#include <linux/linux_logo.h>
  #include <linux/list.h>
+#include <linux/math.h>
  #include <linux/module.h>
+#include <linux/overflow.h>
  #include <linux/printk.h>
  #include <linux/types.h>
  
@@ -88,6 +92,42 @@ static const struct drm_panic_line logo_ascii[] = {
        PANIC_LINE(" \\___)=(___/"),
  };
  
+#ifdef CONFIG_LOGO
+static const struct linux_logo *logo_mono;
+
+static int drm_panic_setup_logo(void)
+{
+       const struct linux_logo *logo = fb_find_logo(1);
+       const unsigned char *logo_data;
+       struct linux_logo *logo_dup;
+
+       if (!logo || logo->type != LINUX_LOGO_MONO)
+               return 0;
+
+       /* The logo is __init, so we must make a copy for later use */
+       logo_data = kmemdup(logo->data,
+                           size_mul(DIV_ROUND_UP(logo->width, BITS_PER_BYTE), 
logo->height),
+                           GFP_KERNEL);
+       if (!logo_data)
+               return -ENOMEM;
+
+       logo_dup = kmemdup(logo, sizeof(*logo), GFP_KERNEL);
+       if (!logo_dup) {
+               kfree(logo_data);
+               return -ENOMEM;
+       }
+
+       logo_dup->data = logo_data;
+       logo_mono = logo_dup;
+
+       return 0;
+}
+
+device_initcall(drm_panic_setup_logo);
+#else
+#define logo_mono      ((const struct linux_logo *)NULL)
+#endif
+
  /*
   * Color conversion
   */
@@ -452,15 +492,22 @@ static void draw_panic_static_user(struct 
drm_scanout_buffer *sb)
        u32 bg_color = convert_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 logo_width, logo_height;
  
  	if (!font)
                return;
  
  	r_screen = DRM_RECT_INIT(0, 0, sb->width, sb->height);
  
-	r_logo = DRM_RECT_INIT(0, 0,
-                              get_max_line_len(logo_ascii, logo_ascii_lines) * 
font->width,
-                              logo_ascii_lines * font->height);
+       if (logo_mono) {
+               logo_width = logo_mono->width;
+               logo_height = logo_mono->height;
+       } else {
+               logo_width = get_max_line_len(logo_ascii, logo_ascii_lines) * 
font->width;
+               logo_height = logo_ascii_lines * font->height;
+       }
+
+       r_logo = DRM_RECT_INIT(0, 0, logo_width, logo_height);
        r_msg = DRM_RECT_INIT(0, 0,
                              min(get_max_line_len(panic_msg, msg_lines) * 
font->width, sb->width),
                              min(msg_lines * font->height, sb->height));
@@ -471,10 +518,14 @@ static void draw_panic_static_user(struct 
drm_scanout_buffer *sb)
        /* Fill with the background color, and draw text on top */
        drm_panic_fill(sb, &r_screen, bg_color);
  
-	if ((r_msg.x1 >= drm_rect_width(&r_logo) || r_msg.y1 >= drm_rect_height(&r_logo)) &&
-           drm_rect_width(&r_logo) <= sb->width && drm_rect_height(&r_logo) <= 
sb->height) {
-               draw_txt_rectangle(sb, font, logo_ascii, logo_ascii_lines, false, 
&r_logo,
-                                  fg_color);
+       if ((r_msg.x1 >= logo_width || r_msg.y1 >= logo_height) &&
+           logo_width <= sb->width && logo_height <= sb->height) {
+               if (logo_mono)
+                       drm_panic_blit(sb, &r_logo, logo_mono->data, 
DIV_ROUND_UP(logo_width, 8),
+                                      fg_color);
+               else
+                       draw_txt_rectangle(sb, font, logo_ascii, logo_ascii_lines, 
false, &r_logo,
+                                          fg_color);
        }
        draw_txt_rectangle(sb, font, panic_msg, msg_lines, true, &r_msg, 
fg_color);
  }
diff --git a/drivers/video/logo/Kconfig b/drivers/video/logo/Kconfig
index b7d94d1dd1585a84..ce6bb753522d215d 100644
--- a/drivers/video/logo/Kconfig
+++ b/drivers/video/logo/Kconfig
@@ -8,6 +8,8 @@ menuconfig LOGO
        depends on FB_CORE || SGI_NEWPORT_CONSOLE
        help
          Enable and select frame buffer bootup logos.
+         Monochrome logos will also be used by the DRM panic handler, if
+         enabled.
  
  if LOGO