How do I change the framebuffer mode?

asked 2015-07-18 21:58:26 -0500

Summit gravatar image

updated 2015-07-19 19:19:13 -0500

mether gravatar image

fbset returns ioctl FBIOPUT_VSCREENINFO: Invalid argument when running something like:
fbset -g 1024 768 1024 768 32 -t 12714 128 32 16 4 128 4
no matter what I try (sudo, explicit database, frame buffer device). I found a way to echo directly to a fb0 parameter in /sys/... , but that was not Fedora documentation and I do not want to be blind on my desktop.
I've been having lot's of trouble setting up a 21:9 2560x1080 monitor. Fedora (and other distros) maxes out at 1920x1080. That being said I'm willing to resort to kernel parameters and even custom kernels if it is necessary.
I suspect the frame buffer because all was well under proprietary Catalyst drivers (good xrandr resolution and all) but the frame buffer mode was strange:
mode "1024x768-76"
# D: 78.653 MHz, H: 59.949 kHz, V: 75.694 Hz
geometry 1024 768 1024 768 32
timings 12714 128 32 16 4 128 4
rgba 8/16,8/8,8/0,8/24
But I can't even seem to change my frame buffer mode. The mode above is the mode I'm trying to set and I added it to fb.modes. With the radeon drivers, xrandr custom modes (as per EDID) do not work and I believe it's because the frame buffer mode does not seem to change with xrandr.
If you need /var/log/Xorg.0.log or dmesg, please let me know.
Linux Prime 4.0.7-300.fc22.x86_64 #1 SMP Mon Jun 29 22:15:06 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

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But the framebuffer is different from Xorg! Why do you resize the framebuffer? Do you sometimes not use Xorg?

NuuN gravatar imageNuuN ( 2015-07-19 00:25:06 -0500 )edit

@NuuN I'm trying to replicate the settings that the proprietary catalyst driver used. It seems to be the only configuration that works.

Summit gravatar imageSummit ( 2015-07-19 14:33:14 -0500 )edit

@Summit, if I memory serves, the present framebuffer for nouveau is managed by KMS. Maybe you could find options to fit that by researching KMS instead. Look at man drm-kms.

NuuN gravatar imageNuuN ( 2015-07-19 15:32:31 -0500 )edit

@NuuN drm.debug=6 at boot and I found the needle in the haystack. dmesg gives: [ 58.552132] [drm:drm_mode_debug_printmodeline] Modeline 59:"2560x1080" 60 185580 2560 2624 2688 2784 1080 1083 1093 1111 0x48 0xa [ 58.552134] [drm:drm_mode_prune_invalid] Not using 2560x1080 mode: CLOCK_HIGH My monitor is rated for 240MHz (as per monitor-edid)... I'm considering filing a bug.

Summit gravatar imageSummit ( 2015-07-22 16:24:16 -0500 )edit