Re: Failure to use 3840x2160 30hz with Intel 620 chipset

[Felix Miata <mrmazda@earthlink.net>]

Pierre Couderc composed on 2021-07-08 22:42 (UTC+0200):

> I have a problem when trying a 4K display with Acer swift5. They say 
> that 3840x2160 30hz is supported...

> When I try (under bullseye) :

> gtf  3840 2160 30

> xrandr --newmode  "3840x2160_30.00"  339.57  3840 4080 4496 5152 2160 
> 2161 2164 2197  -HSync +Vsync
> xrandr --addmode HDMI-1   3840x2160_30.00
> xrandr --output HDMI-1 --mode "3840x2160_30.00"

> the PC crashes (all is black, need to power off).
											
You should have no need of gtf or mode creation with 620 graphics. Mode creation
via xrandr is an anachronism. X knows very well how to auto generate modes when
provided with needed specs. If EDID, the usual source for the data, is broken,
then provide the specs via:

	/etc/X11/xorg.conf.d/50-monitor.conf

containing the horizontal sync and vertical refresh rates for your display, e.g.:

	Section "Monitor"
	    Identifier	"Default Monitor"
		HorizSync	28-85
		VertRefresh	50-100
	EndSection

Usually you can get these two specs if not elsewhere using:

	hwinfo --monitor

As to why you're having the problem, let us see the resulting URL from:

	pastebinit /var/log/Xorg.0.log

as a start.
-- 
Evolution as taught in public schools is, like religion,
	based on faith, not based on science.

 Team OS/2 ** Reg. Linux User #211409 ** a11y rocks!

Felix Miata