Arch Linux

davispuh

Member

From: Latvia

Registered: 2014-03-31

Posts: 10

[Solved] Blank screen for old CRT montor (Compaq P1210) with KMS

Posted it here in case someone encounters something similar.

I decided to install Arch on this quite old PC (Intel Pentium 4 and ATI Radeon HD 2600 Pro AGP)

But when booting latest (2014.09.03) installation, right after kernel decompression screen went blank. KMS was using wrong settings for monitor.  Something with EDID isn't working. So easy workaround for this is to append "drm_kms_helper.edid_firmware=edid/1600x1200.bin" to Kernel parameters. In syslinux can just press tab and type it. After installation need to add it to boot entry so it's persistent. Note that there are only few builtin EDID profiles and you must use one which is supported by your monitor. More info in wiki Forcing modes and EDID

Next, I also needed to force X to use different frequency for monitor because that builtin EDID profile uses 60 Hz and this monitor can do more.
So I generated modeline with "cvt 1600 1200 85" and created /etc/X11/xorg.conf.d/10-monitor.conf with

Section "Monitor"
        Identifier   "DVI-0"
        Modeline     "1600x1200_85.00"  235.00  1600 1728 1896 2192  1200 1203 1207 1262 -hsync +vsync
        Option       "PreferredMode" "1600x1200_85.00"
EndSection

(Identifier must match respective monitor connector.  xrandr -q will show)

And that's all.  Arch Linux works perfectly on this old setup. Also installed KDE workspace and without knowing couldn't tell it's so old PC

Last edited by davispuh (2014-09-07 03:55:24)