#1 2022-01-14 06:54:39

Garan_CA

New Member

Registered: 2022-01-14

Posts: 1

2nd monitor (DisplayPort) not being detected old ATI GPU

I'm a new bunsenlabs user and I'm having some trouble with my 2nd monitor.
I have 2 identical Lenovo monitors attached to my desktop.
1 via HDMI and 1 via Display port.

The dual monitors work in Windows 10, Ubuntu, Mint 20.3, Zorin 16 Lite automatically, but bunsenlab is not detecting the 2nd monitor.

It's a brand new fresh install.

garan@bunsen:~$ xrandr -q
Screen 0: minimum 320 x 200, current 2560 x 1440, maximum 8192 x 8192
VGA-1 disconnected primary (normal left inverted right x axis y axis)
HDMI-1 connected 2560x1440+0+0 (normal left inverted right x axis y axis) 597mm x 336mm
   2560x1440     59.95*+  74.78  
   1920x1200     59.95  
   1920x1080     60.00    60.00    50.00    59.94  
   1920x1080i    60.00    50.00    59.94  
   1680x1050     59.88  
   1280x1024     75.02    70.00    60.02  
   1440x900      59.90  
   1152x864      75.00  
   1280x720      60.00    50.00    59.94  
   1024x768      75.03    70.07    60.00  
   832x624       74.55  
   800x600       72.19    75.00    60.32  
   720x576       50.00  
   720x480       60.00    59.94  
   640x480       75.00    72.81    66.67    60.00    59.94  
   720x400       70.08  

garan@bunsen:~$ xrandr --listproviders
Providers: number : 2
Provider 0: id: 0x8c cap: 0xf, Source Output, Sink Output, Source Offload, Sink Offload crtcs: 2 outputs: 2 associated providers: 0 name:modesetting
Provider 1: id: 0x45 cap: 0xf, Source Output, Sink Output, Source Offload, Sink Offload crtcs: 4 outputs: 2 associated providers: 0 name:CAICOS @ pci:0000:01:00.0

garan@bunsen:~$ lspci | grep VGA
00:02.0 VGA compatible controller: Intel Corporation 4th Generation Core Processor Family Integrated Graphics Controller (rev 06)
01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Caicos [Radeon HD 6450/7450/8450 / R5 230 OEM]

*-display
                description: VGA compatible controller
                product: Caicos [Radeon HD 6450/7450/8450 / R5 230 OEM]
                vendor: Advanced Micro Devices, Inc. [AMD/ATI]
                physical id: 0
                bus info: pci@0000:01:00.0
                version: 00
                width: 64 bits
                clock: 33MHz
                capabilities: vga_controller bus_master cap_list rom
                configuration: driver=radeon latency=0

Any help to fix the problem is greatly appreciated.

I love the fact that bunsenlabs is so fast & lightweight compared to everything else I tried.

Last edited by Garan_CA (2022-01-14 06:57:16)

nobody

The Great

Registered: 2015-08-10

Posts: 3,655

Re: 2nd monitor (DisplayPort) not being detected old ATI GPU

The issue here is likely that it's a muxless dual graphics card. You have both an AMD graphics card and an Intel graphics card in that laptop and it's likely that the two outputs are connect to one of the cards each. It seems from your output here that the Intel card (screen 0) is active while the dedicated Radeon card is not (Provider 1), and thus the Radeon card's output doesn't show up.

First quick try would be to make sure the package xserver-xorg-video-radeon is installed, then reboot if it wasn't installed.

Second quick try would be to make sure the backports repo of Debian is enabled and install backport versions of both the Linux kernel and mesa.

Most thorough approach would be to boot a working distro, one of those you listed, save and copy the Xorg log file /var/log/Xorg*.log, then boot BL with the backports  installed as above and also get a copy of the Xorg log file, then compare those two logs side by side to see what's needed for this setup to work. In the utmost, the most recent BL (which is based on Debian 10) is not new enough to include new library versions with fixed/improved open source drivers.

In the old days your issue would have been resolved by installing the AMD fglrx / catalyst driver but AMD does only support the AMDGPU drivers now, which don't support old cards like yours, thus the solution is using the open-source radeon driver from mesa, which receives continuous fixes.