Hi Jocelyn, On Wed, Dec 4, 2024 at 6:41 PM Jocelyn Falempe <jfalempe@xxxxxxxxxx> wrote: > drm_log is a simple logger that uses the drm_client API to print the kmsg boot log on the screen. > This is not a full replacement to fbcon, as it will only print the kmsg. > It will never handle user input, or a terminal because this is better done in userspace. > > If you're curious on how it looks like, I've put a small demo here: > https://people.redhat.com/jfalempe/drm_log/drm_log_draft_boot_v2.mp4 > > Design decisions: > * It uses the drm_client API, so it should work on all drm drivers from the start. > * It doesn't scroll the message, that way it doesn't need to redraw the whole screen for each new message. > It also means it doesn't have to keep drawn messages in memory, to redraw them when scrolling. > * It uses the new non-blocking console API, so it should work well with PREEMPT_RT I gave this a try on Koelsch (R-Car M2-W), using rcar-du. Unfortunately I don't see any kernel messages, and my monitor complains about no signal. Does this require special support from the driver? CONFIG_DRM_CLIENT=y CONFIG_DRM_CLIENT_LIB=y CONFIG_DRM_CLIENT_SELECTION=y CONFIG_DRM_CLIENT_SETUP=y CONFIG_DRM_CLIENT_LOG=y # CONFIG_DRM_CLIENT_DEFAULT_FBDEV is not set CONFIG_DRM_CLIENT_DEFAULT_LOG=y CONFIG_DRM_CLIENT_DEFAULT="log" Switching to fbdev gives a working display, as before: CONFIG_DRM_CLIENT_DEFAULT_FBDEV=y # CONFIG_DRM_CLIENT_DEFAULT_LOG is not set CONFIG_DRM_CLIENT_DEFAULT="fbdev" Thanks! Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx 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
