Raspberry Pi 4: Garbled output to monitor with drm

[WebReflection]

The issue/visual result is pretty identical to the one described in #156, basically even if I force the Pi 4 to start at 1280x720, when I use cog -P drm $PAGE the output switches to Full HD (my TV resolution) and I see stripes:

Current cog version is 0.6, I am using cairo-glesv2, and I have zero issues via fdo, but I was hoping I could get rid of weston entirely and simply use the DRM version of cog.

Am I missing some flag to force current screen resolution or to limit width and height? 'cause I couldn't find any flag in the drm.c related file, so I am not sure there's a workaround for this.

Thanks.

[aperezdc]

The issue/visual result is pretty identical to the one described in #156, basically even if I force the Pi 4 to start at 1280x720, when I use cog -P drm $PAGE the output switches to Full HD (my TV resolution) and I see stripes:

There could be similar issue related to the RPi4 pixel format. We are passing the buffer pixel format directly to drmModeAddFB2WithModifiers() or drmModeAddFB2() so I suppose there can be some issue in libdrm, or in how Cog is doing this. I do not have a RPi4 myself to debug this myself, though 😑️

Am I missing some flag to force current screen resolution or to limit width and height? 'cause I couldn't find any flag in the drm.c related file, so I am not sure there's a workaround for this.

Currently the DRM platform plug-in will pick the resolution reported by the screen as preferred (typically the one with highest resolution which is not interlaced), or if the screen does not report a preferred resolution the code chooses the one with the most area (width × height). I have created #198 to track adding support to manually specify an output resolution.

[WebReflection]

Actually, the flag works as intended, but I haven't tried in full HD. Will do in few minutes and report back, but I suspect the PI at full HD has issues in general

[clopez]

Try passing -O renderer=gles to cog.

Example:

cog -P drm -O renderer=gles https://wpewebkit.org

[WebReflection]

my bad, I should've closed this ages ago ... as I've had no issues in a long time. Sorry for keeping it open.