separate framebuffer per head?

Slippery Jim · Apprentice Joined: 08 Jan 2005 Posts: 284

I want to have separate, independent framebuffers for each of the outputs on my radeon 7750 card, but I only get the single /dev/fb0 created on bootup. Also, it appears to be mirrored across all my outputs. There must be a config option for this somewhere either in the kernel, in grub, or in udev, but I can't find it. Can anyone point me in the right direction?

s4e8 · Guru Joined: 29 Jul 2006 Posts: 311

No, drm guys think fbdev/fbcon is legacy, they are trying to remove fbdev completely.

chithanh · Posted: Thu Mar 31, 2016 4:12 pm Post subject:

You may be able to use both monitors with KMSCON. It got removed from Gentoo however due to lack of maintenance.
For separate, independent heads you will probably have to wait until DRM modesetting nodes are implemented.

Slippery Jim · Apprentice Joined: 08 Jan 2005 Posts: 284

Didn't realize fbdev and kms framebuffer were separate subsystems; I just assumed that fbdev was now implemented on top of KMS/DRM, or something like that. Guess I'll have to dig into the DRM interface to see if I can drive the outputs directly. Thanks for the heads-up, guys.