On 11/18/22 14:18, Thomas Zimmermann wrote: [...] >> >> In the cover letter you said "color depth is the number of color and alpha bits >> that affect image composition" but it should be "only the number of color bits >> excluding the alpha bits" a better description right? > > I was looking at drm_fourcc.c, where alpha formats, such as ARGB888, > have alpha included in their depth value. [1] Alpha obviously effects > image composition. > > But meaning of these terms is somewhat fuzzy, as the command-line > arguments of video= include a BPP value that is more similar to DRM's > depth value. > I see. > [1] > https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/drm_fourcc.c#L175 > >> >> I also wonder if instead of using a 24 magic number, TRUE_COLOR_DEPTH constant >> macro or XRGB8888_COLOR_DEPTH could be defined? > > Please not. What we should do is to replace the preferred depth and bpp > with a single format constant (as 4cc or drm_format_info) that > designates a preferred default. From that format constant, the values > exported to userspace and fbdev emulation should be retrieved automatically. > > If anything, I'd add a TODO item to convert the DRM codebase. > Right. That makes more sense indeed. -- Best regards, Javier Martinez Canillas Core Platforms Red Hat
