Fossapup64 screen resolution problem

[rustypup]

Hi all. Looking for help and advice regarding my freshly installed fossapup. I can't seem to get the correct screen resolution. I need 2560x1440 and despite selecting this with Xorg Wizard, I only get 1920x1080. The weird thing is, I never has the problem with Xenialpup or Bionicpup, both of those run at 2560x1440 no bother. Video report below...

VIDEO REPORT: fossapup64, version 9.5
Processor: AMD FX(tm)-6300 Six-Core Processor

X.Org X Server 1.20.8
X Protocol Version 11, Revision 0

Chip description:


01:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Cape Verde XT [Radeon HD 7770/8760 / R7 250X] [1002:683d]
Subsystem: XFX Pine Group Inc. Cape Verde XT [Radeon HD 7770/8760 / R7 250X] [1682:3230]
Kernel driver in use: radeon
Kernel modules: radeon, amdgpu

Requested by /etc/X11/xorg.conf:
Resolution (widthxheight, in pixels): 2560x1440
Depth (bits, or planes): 24
Modules requested to be loaded: glx
Drivers requested to be loaded: radeon

Probing Xorg startup log file (/var/log/Xorg.0.log):
Driver loaded (and currently in use): radeon
Loaded modules: dri2 fb glamoregl glx libinput ramdac

Actual rendering on monitor:
Resolution: 1920x1080 pixels (508x285 millimeters)
Depth: 24 planes

direct rendering: Yes
server glx vendor string: SGI
server glx version string: 1.4
OpenGL vendor string: X.Org
OpenGL renderer string: AMD VERDE (DRM 2.50.0, 5.4.53, LLVM 10.0.0)
OpenGL core profile version string: 4.5 (Core Profile) Mesa 20.0.8


Monitor : card0-DP-1
Model : PHL BDM3270
WxH (cm) : 71x40

Any help would be greatly appreciated. I have already tried installing the firmware package using Quickpet.

[Grey]

Hi. You have an interesting problem. My monitor is also 32-inch, but resolution is 1920x1080 maximum.
Try to enter the xrandrshell command in terminal and set the screen resolution in the window that appears.

[rustypup]

Thanks Grey, I will try this. My screen is a 32" QHD Philips which has a native resolution of 2560x1440, so it looks pretty bad running at 1080.

Edit: just tried that. The resolution I need is not listed in the drop down. Max available is 1920x1080. Weird, as Xorg wizard has 2560x1440 available.

[Grey]

That's why I bought Nvidia and installed a proprietary driver

[Adam Li]

AMD Radeon HD 7770 Display Driver 8.932.5.2 for Linux
AMD Radeon™ HD 7770 GHz Edition Previous Drivers

[rustypup]

Ok, so I've got somewhere with this, just in case anyone else has this issue, I'll share.

Open terminal and follow these steps.

Use cvt command to get the modeline info for the desired resolution.

cvt 2560 1440

Then use that info to add a new mode to xrandr like so:

xrandr --newmode "2560x1440_60.00" 312.5 2560 2752 3024 3488 1440 1443 1448 1493 -hsync +vsync

Then add the new mode to your output (mine is DisplayPort-0) like so:

xrandr --addmode DisplayPort-0 "2560x1440_60.00"

Next, force the new mode to your output:

xrandr --output DisplayPort-0 --mode "2560x1440_60.00"

And yeah, that worked. Only thing is, I'm not sure what will happen when I reboot. I may need to add a script to startup - not sure yet!

[bigpup]

Just make sure the save gets updated when you reboot.
At shutdown/reboot, it should say it is updating the save or if you have it set to ask to save. Say yes.
The change should be stored in the save and used, when you next boot, using the save.

[bigpup]

rustypup;

We the Puppy users help each other and Puppy development.

That info on what you did to fix this issue, would be a good topic to post in the How To section of this forum.
Maybe here:
viewforum.php?f=148

Any info on getting AMD hardware working is always needed.

[rustypup]

Ok, so, as expected the changes I made in Xrandr to get my desired screen resolution only hold for that session. And yes, I did save the session before I rebooted. Next I tried adding a script to the startup folder to run the aforementioned xrandr commands. That worked but you would always see the resolution get changed just after you hit the desktop after booting. Not very elegant. So, more digging around on the internet and I found a permanent solution that works 100%. You need to manually edit your xorg.conf so that the monitor section looks like this...

Section "Monitor"
Identifier "Monitor0"
# VendorName "Monitor Vendor"
# ModelName "Monitor Model"
# HorizSync 35-81
# VertRefresh 59-76
# #UseModes "Modes0" #monitor0usemodes
Modeline "2560x1440_60.00" 312.25 2560 2752 3024 3488 1440 1443 1448 1493 -hsync +vsync
Option "PreferredMode" "2560x1440_60.00"
EndSection

Obviously, if you are looking for a different resolution that is currently unavailable, use the cvt command in terminal to get the modeline and put that into your xorg.conf.

@bigpup - thanks I will make a new post in the How-To section as you have suggested

[rustypup]

See here for more info viewtopic.php?f=148&p=33273#p33273

[LateAdopter]

There was a commit to add this mode to linux kernel amdgpu about six months ago.
drm/amdgpu: Add new mode 2560x1440
https://gitlab.freedesktop.org/agd5f/li ... 2dfe5b58cb

It seems to be a defect of linux that these things are hard coded when the EDID has the preferred resolution anyway. I guess the earlier Puppies defaulted to Radeon which may be different.

I don't know whether this got backported to stable kernels

EDIT: You may be able to blacklist the amdgpu kernel module and make it use radeon instead. Both support Southern Island and Sea Island GPUs.

[rustypup]

Good information. Thanks LateAdopter