Q4OS Forum

micoots

Member

Registered: 2020-12-25

Posts: 3

4 Displays but can only enable 2

Hi,

I have 4 displays running through 2 dual head cards with DVI output.

Use normally with Windows 10 and recently (a few days ago) decided to try Q4OS.

Intel and AMD video controllers detected. HP desktop is used with 8 cores and 24GB RAM.

I can only get two displays working.

I have searched various things from Q4OS and Debian 10 searches, but can't find anything to get the 4 displays working.

This forum is a last resort, without the 4 screens I regrettably have to go back to Windows 10.

Please help and advise, as I really wish to use Q4OS with Plasma.

Thanks.

micoots

Member

Registered: 2020-12-25

Posts: 3

Re: 4 Displays but can only enable 2

Note I've also tried Trinity installed via the desktop profiler, so tried on both trinity and plasma, same results only two displays work.

Some commands and output:

$ xrandr --listproviders
Providers: number : 2
Provider 0: id: 0xa0 cap: 0xf, Source Output, Sink Output, Source Offload, Sink Offload crtcs: 4 outputs: 2 associated providers: 0 name:CEDAR @ pci:0000:01:00.0
Provider 1: id: 0x47 cap: 0xf, Source Output, Sink Output, Source Offload, Sink Offload crtcs: 3 outputs: 5 associated providers: 0 name:modesetting

$ dmesg | grep -E 'drm|radeon' | grep -iE 'firmware|microcode'
[   13.177409] [drm] Loading CEDAR Microcode
[   13.659170] radeon 0000:01:00.0: firmware: direct-loading firmware radeon/CEDAR_pfp.bin
[   13.834096] radeon 0000:01:00.0: firmware: direct-loading firmware radeon/CEDAR_me.bin
[   13.949774] radeon 0000:01:00.0: firmware: direct-loading firmware radeon/CEDAR_rlc.bin
[   14.021042] radeon 0000:01:00.0: firmware: direct-loading firmware radeon/CEDAR_smc.bin
[   14.143971] radeon 0000:01:00.0: firmware: direct-loading firmware radeon/CYPRESS_uvd.bin

$ lspci -knn | grep -iA3 'vga\|display\|3d'
00:02.0 Display controller [0380]: Intel Corporation Xeon E3-1200 v3/4th Gen Core Processor Integrated Graphics Controller [8086:0412] (rev 06)
        Subsystem: Hewlett-Packard Company Xeon E3-1200 v3/4th Gen Core Processor Integrated Graphics Controller [103c:18e7]
        Kernel driver in use: i915
        Kernel modules: i915
--
00:16.3 Serial controller [0700]: Intel Corporation 8 Series/C220 Series Chipset Family KT Controller [8086:8c3d] (rev 04)
        Subsystem: Hewlett-Packard Company 8 Series/C220 Series Chipset Family KT Controller [103c:18e7]
        Kernel driver in use: serial
00:19.0 Ethernet controller [0200]: Intel Corporation Ethernet Connection I217-LM [8086:153a] (rev 04)
--
01:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Cedar [Radeon HD 7350/8350 / R5 220] [1002:68fa]
        Subsystem: Hewlett-Packard Company Cedar [Radeon HD 7350/8350 / R5 220] [103c:2127]
        Kernel driver in use: radeon
        Kernel modules: radeon

$ lspci |grep VGA
01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Cedar [Radeon HD 7350/8350 / R5 220]

bin

Member

From: U.K.

Registered: 2016-01-28

Posts: 1,301

Re: 4 Displays but can only enable 2

Are you getting one display per card or two from one card and nothing from t'other?

micoots

Member

Registered: 2020-12-25

Posts: 3

Re: 4 Displays but can only enable 2

Hi. Thank you got your reply.

I just checked and to confirm, I have one dual head card with a Y connector going to two monitors (the ones Q4OS picks up and works fine with) and the other two displays using the "DisplayPort" on the back of the PC.

The PC is a HP ProDesk 600 G1 SFF:

https://support.hp.com/au-en/document/c03846648

I can open the PC to confirm configuration (if required), but the displays that Q4OS isn't working with are the 2 DisplayPort cables coming out of the back which is defined in the link above as:

Rear:

    (4) USB 2.0 ports
    (2) USB 3.0 ports, serial (RS-232), PS/2 keyboard (purple), PS/2 mouse (green), VGA (analog), (2) DisplayPort with multi-stream, 3.5 mm audio in and out jacks, RJ-45 Network interface port

Without opening the PC not sure how to DisplayPort ports are supplied. Please advise if I should open the case and take photo's etc.

Thanks.

Last edited by micoots (2020-12-26 05:05)

bin

Member

From: U.K.

Registered: 2016-01-28

Posts: 1,301

Re: 4 Displays but can only enable 2

OK - so the problem is getting DisplayPort working along with the Radeon card.
Ostensibly the Cedar chipset is supported by the standard radeon driver.
We need to work out whether it is a straight Debian doesn't work with the AMD card and displayport or whether it is just getting confused by having 2 graphics cards.
It may not be the 'right' way, but in your shoes I would first of all just pull the Intel card and see if you get a working display with the onboard setup. If that works then it's simply a question of getting xorg to behave. If it doesn't then we have a different issue.
I would suggest that you grab the Testing version of Q4OS https://sourceforge.net/projects/q4os/files/testing/ and also the Ubuntu based version as well https://sourceforge.net/projects/quark-os/files/
These may help if they will have later drivers.
By the way - are you going DisplayPort to DVI or to HDMI?