On Mon, 30 Nov 2020, Daniel Vetter wrote:

On Mon, Nov 30, 2020 at 09:31:15AM -0500, Mikulas Patocka wrote:

quoted

The framebuffer driver supports programs running full-screen directly on 
the framebuffer console, such as web browser "links -g", image viewer 
"fbi", postscript+pdf viewer "fbgs", ZX Spectrum emulator "fuse-sdl", 
movie player "mplayer -vo fbdev". The DRM driver doesn't run them.

Hm this should in general work on drm drivers. Without that it's clear the
switch-over isn't really ready yet.

I fixed it with this patch two years ago: 
https://lists.freedesktop.org/archives/dri-devel/2018-June/179023.html

But the patch never went through and the fb_defio feature was removed in 
the kernel 5.6 (commit d0c4fc5a4814e431c15272935c8dc973c18073aa).


Without fb_defio, the only other possibility how to update the screen is 
the ioctl DRM_IOCTL_MODE_DIRTYFB. But this ioctl requires master mode, so 
user programs like "links -g" can't issue it.

Mikulas