Bug 90083

Summary: unusable desktop with dell u2515h
Product: xorg Reporter: Sebastian Bauer <dev.frandom>
Component: Driver/RadeonAssignee: xf86-video-ati maintainers <xorg-driver-ati>
Status: RESOLVED MOVED QA Contact: Xorg Project Team <xorg-team>
Severity: major    
Priority: medium    
Version: git   
Hardware: x86-64 (AMD64)   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Attachments:
Description Flags
xorg.log loop monitor modes
none
xrandr output
none
dmesg output none

Description Sebastian Bauer 2015-04-18 07:23:21 UTC
Created attachment 115171 [details]
xorg.log loop monitor modes

Hello,

first things first: i do not know whether this behavior is caused by the radeon driver or the xorg server as i was not able to reproduce it with a wayland live cd. But as the ati-drivers did not show the same symptoms my best guess is the radeon driver.

The situation: 
Recently i bought a new monitor (dell u2515h) for my system (gentoo (mostly stable), amd fx 8350, amd hd 7750) as a replacement for my previous one (dell u2412m). Everything (boot, sddm) went well until i started the plasma 5 desktop. The login splash' progress bar reached around 70% but after that no progress at all. Starting an empty xsession with xterm only is possible, but after launching the kwin window manager, the reason showed up, why the plasma desktop didn't want to start successfully: the mouse movement stuttered and was horrible slow. The xorg.log (see attachment) shows that something causes the xorg server to print the monitor modes over and over again, the only way to stop it is killing the xorg server.

Switching to the xfce desktop helped temporarily, but it is very disappointing, as i got the same stuttering after starting the desktop. Just after the 5th or 6th try (sometimes more, sometimes less) the effect does not show up and i get a usable desktop.

So i tried to reproduce this situation in a plain xsession with xterm only. Setting the dpi via xrandr to 118 was the easiest way to raise the mouse stuttering. To make things more interestingly, very rarely the command was successful. Then i even was able to start kwin and some kde applications, but as soon as i started plasma the mouse stuttering was back.

I have testet different linux distributions, they all behave the same. Xorg-Server (currently 1.16.4, temporarily 1.17.1) does not change a thing. Using the ati-driver is a solution to this problem, but not suitable for me (and possibly for many others).

I'll provide any information (which i'm capable of) you need to resolve this issue.

Thanks!
Comment 1 Sebastian Bauer 2015-04-18 07:24:12 UTC
Created attachment 115172 [details]
xrandr output
Comment 2 Alex Deucher 2015-04-19 15:45:50 UTC
Please attach your dmesg output as well.
Comment 3 Alex Deucher 2015-04-19 15:47:49 UTC
(In reply to Sebastian Bauer from comment #0)
> I have testet different linux distributions, they all behave the same.
> Xorg-Server (currently 1.16.4, temporarily 1.17.1) does not change a thing.
> Using the ati-driver is a solution to this problem, but not suitable for me
> (and possibly for many others).
>

What do you mean by this?  The ati driver and the radeon driver are the same driver.
Comment 4 Alex Deucher 2015-04-19 15:50:24 UTC
This might be a duplicate of bug 89505.  Can you try the patch in comment 7 of that bug?
Comment 5 Sebastian Bauer 2015-04-19 15:59:42 UTC
Created attachment 115194 [details]
dmesg output
Comment 6 Sebastian Bauer 2015-04-19 16:00:54 UTC
(In reply to Alex Deucher from comment #3)
> (In reply to Sebastian Bauer from comment #0)
> > I have testet different linux distributions, they all behave the same.
> > Xorg-Server (currently 1.16.4, temporarily 1.17.1) does not change a thing.
> > Using the ati-driver is a solution to this problem, but not suitable for me
> > (and possibly for many others).
> >
> 
> What do you mean by this?  The ati driver and the radeon driver are the same
> driver.

Sorry, i'm on gentoo, the fglrx' package is called ati-drivers.
Comment 7 Sebastian Bauer 2015-04-19 16:03:12 UTC
(In reply to Alex Deucher from comment #4)
> This might be a duplicate of bug 89505.  Can you try the patch in comment 7
> of that bug?

Thanks for the reply! Unfortunately, this bug does not apply to my issue as my machine is running kernel 3.19 and the patch is included already.
Comment 8 Sebastian Bauer 2015-04-19 16:04:21 UTC
(In reply to Sebastian Bauer from comment #7)
> (In reply to Alex Deucher from comment #4)
> > This might be a duplicate of bug 89505.  Can you try the patch in comment 7
> > of that bug?
> 
> Thanks for the reply! Unfortunately, this bug does not apply to my issue as
> my machine is running kernel 3.19 and the patch is included already.

Sorry, my bad. I just looked at the link to the git repository. I'll give it a try.
Comment 9 Sebastian Bauer 2015-04-19 16:32:05 UTC
Well, i applied the patch.

The good news: the login into a xfce session did not raised the issue yet (tried it twice).

The not so good news: it still applies to a kde session. By executing the commands:
$ xrandr --dpi 118
$ kwin_x11

i still could reproduce the mouse stuttering as well as the unending outputs to the Xorg.log.
Comment 10 Sebastian Bauer 2015-04-20 17:09:56 UTC
Unfortunaltely, i have to revise this statement. The phenomenon described above happened again when i booted my pc today. Probably, i just got lucky yesterday...

Is there anything i can provide additionally?
Comment 11 Martin Peres 2019-11-19 07:50:04 UTC
-- GitLab Migration Automatic Message --

This bug has been migrated to freedesktop.org's GitLab instance and has been closed from further activity.

You can subscribe and participate further through the new bug through this link to our GitLab instance: https://gitlab.freedesktop.org/xorg/driver/xf86-video-ati/issues/127.

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