Hi Thomas,
On Mon, Oct 14, 2019 at 4:05 PM Thomas Zimmermann tzimmermann@suse.de wrote:
The display mode is set by converting the DRM display mode to an fb_info state and handling it to the fbdev driver's fb_setvar() function. This also requires a color depth, which we take from the value of struct drm_mode_config.preferred_depth
Signed-off-by: Thomas Zimmermann tzimmermann@suse.de
--- a/drivers/gpu/drm/drm_fbconv_helper.c +++ b/drivers/gpu/drm/drm_fbconv_helper.c @@ -919,6 +919,24 @@ static int drm_fbconv_update_fb_var_screeninfo_from_framebuffer( return 0; }
+static int drm_fbconv_update_fb_var_screeninfo_from_simple_display_pipe(
struct fb_var_screeninfo *fb_var, struct drm_simple_display_pipe *pipe)+{
struct drm_plane *primary = pipe->crtc.primary;struct drm_fbconv_modeset *modeset = drm_fbconv_modeset_of_pipe(pipe);if (primary && primary->state && primary->state->fb)return drm_fbconv_update_fb_var_screeninfo_from_framebuffer(fb_var, primary->state->fb,modeset->fb_info->fix.smem_len);fb_var->xres_virtual = fb_var->xres;fb_var->yres_virtual = fb_var->yres;fb_var->bits_per_pixel = modeset->dev->mode_config.preferred_depth;
This looks wrong to me: IMHO bits_per_pixel should be derived from the fourcc format of the _new_ mode to be set...
return 0;+}
/**
- drm_fbconv_simple_display_pipe_mode_valid - default implementation for
struct drm_simple_display_pipe_funcs.mode_valid@@ -950,6 +968,28 @@ bool drm_fbconv_simple_display_pipe_mode_fixup( struct drm_crtc *crtc, const struct drm_display_mode *mode, struct drm_display_mode *adjusted_mode) {
struct drm_simple_display_pipe *pipe =container_of(crtc, struct drm_simple_display_pipe, crtc);struct drm_fbconv_modeset *modeset = drm_fbconv_modeset_of_pipe(pipe);struct fb_var_screeninfo fb_var;int ret;if (!modeset->fb_info->fbops->fb_check_var)return true;drm_fbconv_init_fb_var_screeninfo_from_mode(&fb_var, mode);ret = drm_fbconv_update_fb_var_screeninfo_from_simple_display_pipe(&fb_var, &modeset->pipe);if (ret)return true;ret = modeset->fb_info->fbops->fb_check_var(&fb_var, modeset->fb_info);
... hence this fails if the requested mode is valid with the new fourcc format, but invalid with the old (but preferred) depth. E.g. due to bandwidth limitations, a high-resolution mode is valid with a low color depth, while a high color depth is limited to lower resolutions.
Unfortunately we do not know the new fourcc format here, as both drm_simple_display_pipe_funcs.mode_{valid,fixup}() are passed the mode (from drm_mode_set.mode), but not the new format (from drm_mode_set.fb->format).
Am I missing something? Is the new format available in some other way? Thanks!
if (ret < 0)return false;drm_mode_update_from_fb_var_screeninfo(adjusted_mode, &fb_var);return true;} EXPORT_SYMBOL(drm_fbconv_simple_display_pipe_mode_fixup);
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds