Re: [PATCH] drm: Don't return unsupported formats in drm_mode_legacy_fb_format

[Thomas Zimmermann]

Hi,

thanks for the patch.
Am 10.03.24 um 16:28 schrieb Frej Drejhammar:
[...]
        size = cmd.pitches[0] * cmd.height;
diff --git a/drivers/gpu/drm/tiny/ofdrm.c b/drivers/gpu/drm/tiny/ofdrm.c
index ab89b7fc7bf6..ded868601aea 100644
--- a/drivers/gpu/drm/tiny/ofdrm.c
+++ b/drivers/gpu/drm/tiny/ofdrm.c
@@ -100,14 +100,14 @@ static const struct drm_format_info 
*display_get_validated_format(struct drm_dev
  
  	switch (depth) {
        case 8:
-               format = drm_mode_legacy_fb_format(8, 8);
+               format = drm_mode_legacy_fb_format(dev, 8, 8);
                break;
        case 15:
        case 16:
-               format = drm_mode_legacy_fb_format(16, depth);
+               format = drm_mode_legacy_fb_format(dev, 16, depth);
                break;
        case 32:
-               format = drm_mode_legacy_fb_format(32, 24);
+               format = drm_mode_legacy_fb_format(dev, 32, 24);
                break;

This will break ofdrm, which needs the returned value as-is to build its 
internal list of plane formats.

I suggest to switch all fbdev code over to drm_driver_legacy_fb_format 
<https://elixir.bootlin.com/linux/latest/C/ident/drm_driver_legacy_fb_format>() 
first and then modify the format indrm_driver_legacy_fb_format 
<https://elixir.bootlin.com/linux/latest/C/ident/drm_driver_legacy_fb_format>() 
after reading it from drm_fb_legacy_fb_format(). I can help a bit with 
testing the fbdev changes.

Best regards
Thomas


        default:
                drm_err(dev, "unsupported framebuffer depth %u\n", depth);
diff --git a/drivers/gpu/drm/xe/display/intel_fbdev_fb.c 
b/drivers/gpu/drm/xe/display/intel_fbdev_fb.c
index 51ae3561fd0d..a38a8143d632 100644
--- a/drivers/gpu/drm/xe/display/intel_fbdev_fb.c
+++ b/drivers/gpu/drm/xe/display/intel_fbdev_fb.c
@@ -32,7 +32,8 @@ struct drm_framebuffer *intel_fbdev_fb_alloc(struct 
drm_fb_helper *helper,
  
  	mode_cmd.pitches[0] = ALIGN(mode_cmd.width *
                                    DIV_ROUND_UP(sizes->surface_bpp, 8), 
XE_PAGE_SIZE);
-       mode_cmd.pixel_format = drm_mode_legacy_fb_format(sizes->surface_bpp,
+       mode_cmd.pixel_format = drm_mode_legacy_fb_format(dev,
+                                                         sizes->surface_bpp,
                                                          sizes->surface_depth);
  
  	size = mode_cmd.pitches[0] * mode_cmd.height;
diff --git a/include/drm/drm_fourcc.h b/include/drm/drm_fourcc.h
index ccf91daa4307..75d06393a564 100644
--- a/include/drm/drm_fourcc.h
+++ b/include/drm/drm_fourcc.h
@@ -310,7 +310,8 @@ const struct drm_format_info *drm_format_info(u32 format);
  const struct drm_format_info *
  drm_get_format_info(struct drm_device *dev,
                    const struct drm_mode_fb_cmd2 *mode_cmd);
-uint32_t drm_mode_legacy_fb_format(uint32_t bpp, uint32_t depth);
+uint32_t drm_mode_legacy_fb_format(struct drm_device *dev,
+                                  uint32_t bpp, uint32_t depth);
  uint32_t drm_driver_legacy_fb_format(struct drm_device *dev,
                                     uint32_t bpp, uint32_t depth);
  unsigned int drm_format_info_block_width(const struct drm_format_info *info,

base-commit: b9511c6d277c31b13d4f3128eba46f4e0733d734

--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)