External monitor not getting highest resolution

[Markus Kilås]

Hi,

When connecting my external monitor to my Dell laptop I don't get the
option of the preferred resolution "2560x1440" for the external monitor
when using Qubes OS (3.2).

Booting with Ubuntu on the same machine I have the option of resolutions
up to "2560x1440" for the external monitor.

xrandr shows:
---
Screen 0: minimum 8 x 8, current 5120 x 1800, maximum 32767 x 32767
eDP1 connected 3200x1800+0+0 (normal left inverted right x axis y axis)
346mm x 194mm
3200x1800 59.98*+
2880x1620 60.00
2560x1440 60.00
2048x1536 60.00
1920x1440 60.00
...snip...
DP1 disconnected (normal left inverted right x axis y axis)
HDMI1 connected 1920x1080+3200+0 (normal left inverted right x axis y
axis) 597mm x 336mm
1920x1080 60.00* 50.00 50.00 59.94
1920x1080i 60.00 50.00 59.94
1680x1050 59.88
1280x1024 75.02 60.02
...snip...
HDMI2 disconnected (normal left inverted right x axis y axis)
VIRTUAL1 disconnected (normal left inverted right x axis y axis)
---

In both cases I am running with the nouveau driver.

Any ideas?

Cheers,
Markus

[Pagebao]

Same thing is happening to me since the last Dom0 update. My ultrawide 29" LG external screen stopped working at the native 2560x1080 resolution and instead is working at 1920x1080.

I have a Lenovo Thinkpad T430s. I was using nouveau driver but the same thing is happening with the integrated Intel graphic card.

Fortunately I had a full backup from August 9 so, reinstalling Qubes 3.2 and restoring Dom0 and all the VM the problem is, temporarily, fixed and I have back 2560x1080 resolution.

But the most maddening thing is that I tried several different distro (Linux Mint 18.2, MX 16.0, Manjaro) and I have the same problem. Only 1920x1080px. In the previous 1.5 years I had no problem of resolution with Qubes 3.2 and Linux Mint 18.1.

Tried cvt and xrandr --newmode and --addmode to no avail so far (no effect on Qubes, screen blanked on Linux Mint).

Again, any idea?

Thanks

[Markus Kilås]

On 09/08/2017 06:17 AM, Pagebao wrote:
> Same thing is happening to me since the last Dom0 update. My ultrawide 29" LG external screen stopped working at the native 2560x1080 resolution and instead is working at 1920x1080.

Oh, that is interesting to know. I did not know this was a regression as
I did not use external monitor before.

>
> I have a Lenovo Thinkpad T430s. I was using nouveau driver but the same thing is happening with the integrated Intel graphic card.
>
> Fortunately I had a full backup from August 9 so, reinstalling Qubes 3.2 and restoring Dom0 and all the VM the problem is, temporarily, fixed and I have back 2560x1080 resolution.
>
> But the most maddening thing is that I tried several different distro (Linux Mint 18.2, MX 16.0, Manjaro) and I have the same problem. Only 1920x1080px. In the previous 1.5 years I had no problem of resolution with Qubes 3.2 and Linux Mint 18.1.
>

So it could be more of generic Linux issue then? Some problem with
certain kernel or nouveau versions perhaps?

> Tried cvt and xrandr --newmode and --addmode to no avail so far (no effect on Qubes, screen blanked on Linux Mint).
>
> Again, any idea?>
> Thanks
>

Anything else one can try to resolve this?

Cheers,
Markus

[yura...@gmail.com]

Did you try going back to the previous kernel? The 4.9.35-20? or even the 4.4'ish version if its still in your system?
Also it may not be relevant as my problem with the new kernel (4.9.45-21) is of a seemingly very different nature (didn't boot due to wanting root account, whatever odd bug was causing that error). Albeit I never made it as far to see whether I lost my resolution as well while running the new kernel.

Assuming you haven't gone back to older kernels before, it's easy to do without uninstalling/installing anything. If you got Grub2 (Legacy Qubes install mode), then just change to the old kernel during early boot in Grub2's advance menu. If you boot up with UEFI/EFI then you need to change the default boot kernel in the /boot/efi/Qubes/xen.conf (somewhere there abouts. Be careful though, wrong settings will make your system unable to boot up).

Obviously far easier to quickly change with Grub2, but it isn't much of a hassle either with editing the xen.cong file if you boot via the modern UEFI instead. Just be careful with the settings.

Also if it may be of any help, I run Qubes with 3840x2160, 4k resolution with kernel 4.9.35-20, nvidia/integrated Intel-M processor graphics, and XFCE4 as my DE. As mentioned earlier, I'm holding back on the current new Dom0 update with the 4.9.45-21, since it gives me boot issues. Furthermore, I have a lot of issues getting my HDMI TV back on my laptop after suspend/hibernation on my current older kernel. Also if I unplug the HDMI, etc. usually I need to go into "xfce4-display" and turn on the screen manually. Maybe its related to some of the black screen mentioned issues, albeit it might be different too.

I'm afraid I can't try help with anything deeper if the problem still persists. Remember to make backups before experimenting with solutions though, it's such a pain to loose things...

If kernels are a suspect, we should list our kernels in case we can find clues. Try throw "uname -r" in your Dom0 terminal to list it.

[Markus Kilås]

On 09/20/2017 10:16 PM, yura...@gmail.com wrote:
> On Wednesday, September 20, 2017 at 3:16:59 PM UTC, Markus Kilås wrote:
>> On 09/08/2017 06:17 AM, Pagebao wrote:
>>> Same thing is happening to me since the last Dom0 update. My ultrawide 29" LG external screen stopped working at the native 2560x1080 resolution and instead is working at 1920x1080.
>>
>> Oh, that is interesting to know. I did not know this was a regression as
>> I did not use external monitor before.
>>
>>>
>>> I have a Lenovo Thinkpad T430s. I was using nouveau driver but the same thing is happening with the integrated Intel graphic card.
>>>
>>> Fortunately I had a full backup from August 9 so, reinstalling Qubes 3.2 and restoring Dom0 and all the VM the problem is, temporarily, fixed and I have back 2560x1080 resolution.
>>>
>>> But the most maddening thing is that I tried several different distro (Linux Mint 18.2, MX 16.0, Manjaro) and I have the same problem. Only 1920x1080px. In the previous 1.5 years I had no problem of resolution with Qubes 3.2 and Linux Mint 18.1.
>>>
>>
>> So it could be more of generic Linux issue then? Some problem with
>> certain kernel or nouveau versions perhaps?
>>
>>> Tried cvt and xrandr --newmode and --addmode to no avail so far (no effect on Qubes, screen blanked on Linux Mint).
>>>
>>> Again, any idea?>
>>> Thanks
>>>
>>
>> Anything else one can try to resolve this?
>>
>> Cheers,
>> Markus
>
> Did you try going back to the previous kernel? The 4.9.35-20? or even the 4.4'ish version if its still in your system?> Also it may not be relevant as my problem with the new kernel
(4.9.45-21) is of a seemingly very different nature (didn't boot due to
wanting root account, whatever odd bug was causing that error). Albeit I
never made it as far to see whether I lost my resolution as well while
running the new kernel.

I believe I was on 4.9.35-20 and had the issue but will double check.

>
> Assuming you haven't gone back to older kernels before, it's easy to do without uninstalling/installing anything. If you got Grub2 (Legacy Qubes install mode), then just change to the old kernel during early boot in Grub2's advance menu. If you boot up with UEFI/EFI then you need to change the default boot kernel in the /boot/efi/Qubes/xen.conf (somewhere there abouts. Be careful though, wrong settings will make your system unable to boot up).
>
> Obviously far easier to quickly change with Grub2, but it isn't much of a hassle either with editing the xen.cong file if you boot via the modern UEFI instead. Just be careful with the settings.

Thank you, this instructions are very helpful.


I am using Grub2 and legacy boot so will try the different kernels on
Tuesday when I am back in office and have access to the monitor.

>
> Also if it may be of any help, I run Qubes with 3840x2160, 4k resolution with kernel 4.9.35-20, nvidia/integrated Intel-M processor graphics, and XFCE4 as my DE. As mentioned earlier, I'm holding back on the current new Dom0 update with the 4.9.45-21, since it gives me boot issues. Furthermore, I have a lot of issues getting my HDMI TV back on my laptop after suspend/hibernation on my current older kernel. Also if I unplug the HDMI, etc. usually I need to go into "xfce4-display" and turn on the screen manually. Maybe its related to some of the black screen mentioned issues, albeit it might be different too.
>
> I'm afraid I can't try help with anything deeper if the problem still persists. Remember to make backups before experimenting with solutions though, it's such a pain to loose things...
>
> If kernels are a suspect, we should list our kernels in case we can find clues. Try throw "uname -r" in your Dom0 terminal to list it.
>

Currently I have uname -a:
Linux dom0 4.9.45-21.pvops.qubes.x86_64 #1 SMP Tue Aug 29 14:21:02 UTC
2017 x86_64 x86_64 x86_64 GNU/Linux

I will retry 4.9.45-20 and also try the oldest I have which is 4.9.35-19.


Cheers,
Markus

[Markus Kilås]

I have the issue with all three available kernels:
4.9.45-21
4.9.35-20
4.9.35-19

Is there a way to install older kernels?

I tried "sudo qubes-dom0-update --action=list kernel-qubes-vm" but those
are the only available.


Regards,
Markus

[Markus Kilås]

Since one of the last updates, high resolution on external monitor is
working. I am still on 4.9.45-21 so it was not a kernel change that
solved it.


Regards,
Markus

[Markus Kilås]

After one of the last updates, the external monitor is working again on
high resolution. It was not a kernel update that solved it as I am still
on 4.9.45-21.

Regards,
Markus

[Markus Kilås]

Actually, I spoke too early but I learned something new:

It is again not working, but I belive the reason it worked for a while
was because the HDMI cable was first connected to an other laptop using
a high resolution (with Ubuntu) and when switching the cable over to my
laptop, I also got the high resolution (!).

// Markus