Re: Display resolution 3840x2160@24rb stopped working after Upgrade from Stretch to Buster

[Jan Michael Greiner]

Thanks to everybody, for all the hints.

I think the way to search in, is to create an edid file and load it at boot.
I searched in this direction before, I just abandoned that way because it did 
not work.

Now the question I have is: How to create that edid file.
The tool I found creates a file in a format, that is not accepted by the 
kernel. 

https://github.com/akatrevorjay/edid-generator/issues/11#issuecomment-531120166

I am using latest Debian (Buster 10.1) and put the generated .bin file in 
/lib/firmware/edid/.

 I added at boot: drm_kms_helper.edid_firmware=edid/3840x2160_24.00_rb.bin

 $ ls -trl 3840x2160*
-rw-r--r-- 1 xxx xxx 492 Aug 24 20:57 3840x2160_24.00_rb.S
-rw-r--r-- 1 xxx xxx 134 Aug 24 20:58 3840x2160_24.00_rb.bin
-rw-r--r-- 1 xxx xxx 388 Aug 24 20:59 3840x2160_24.00_rb.bin.ihex
-rw-r--r-- 1 xxx xxx 838 Aug 24 20:59 3840x2160_24.00_rb.c

Output of dmesg contains - Missing trailing ) on purpose

[drm:drm_load_edid_firmware [drm]] *ERROR* Size of EDID firmware 
"edid/3840x2160_24.00_rb.bin" is invalid (expected 6272, got 134

Re: Display resolution 3840x2160@24rb stopped working after Upgrade from Stretch to Buster

[Jan Michael Greiner]

Dear Charles,

On Monday, September 9, 2019, 1:55:06 PM GMT+2, Charles Curley wrote:

>> On Mon, 9 Sep 2019 10:20:37+ (UTC) Jan Michael Greiner wrote:
>> With Debian Stretch (9.8) I had the display running with 3840x2160
>> resolution at 24Hz reduced blank.


>> [What worked with Debian Stretch (9.9)]
>> export modename="3840x2160_24.00_rb"
 >> xrandr --newmode $modename 209.75 3840 3888 3920 4000 2160 2163 2168 2185 
 >> +HSync -Vsync
 >> xrandr --addmode HDMI-1 $modename
 >> xrandr --output HDMI-1 --mode $modename

 >> [Problem with Debian Buster (10.1)]
 >> xrandr --output XWAYLAND1 --mode $modename
 >> xrandr: Configure crtc0 failed

 >And I take it you want to reproduce that on Debian 10 (buster). I
 > suggest you:
 > * Install arandr.
 >[...]

 Thank you for making me aware of arandr. However, from what I learned:

- arandr is merely a graphical tool for xrandr, so if something does not work 
with xrandr, arandr will not be able to help 

- I did not see any option in the arandr gui to add a non yet existing 
resolution (and I would like to add a 24Hz reduced blank resolution)

 To rephrase my question: How can I enable a custom screen resolution and 
refresh rate (with my specific modeline) with Debian Buster (Wayland)?


 Thank you and best regards

 JM