Graphics problem when users have different screen resolutions

[ricardisimo]

This is happening at work (nVidia card) and here at home (ATI). My user account's resolution is set to 1280*1024, while my wife's is 1024*768 and my son's is 800*600. Sometimes (more than half the time, but not always) when I log one of them out and log myself in, the screen fills with video "noise", for lack of a better word. Everything seems to be vibrating, and everything is an echo of itself all over the screen... the mouse pointer is about three inches off from where it appears on screen. Restarting appears to be the only sure-fire solution, although sometimes the screen will snap itself into shape if I scroll off to one side or the other with the mouse.

Here's my home graphics card: 01:00.0 VGA compatible controller: ATI Technologies Inc RV280 [Radeon 9200 SE] (rev 01)

And here's the work card: 01:00.0 VGA compatible controller: nVidia Corporation NV18 [GeForce4 MX 4000 AGP 8x] (rev c1)

Thanks in advance for any help.

[Bryce Harrington (bryce)]

Hi Ricardisimo,

Thanks for reporting this bug. That's an interesting usage case!

Can you please attach your /etc/X11/xorg.conf file, /var/log/Xorg.0.log file, and the output of running `lspci`? These will help in pinpointing how the system is configured.

Also, if it is possible to take a screenshot or digital photograph of the monitor when it's doing this and attach it, that could help as well. If/when we take this upstream, that can assist the driver developers in figuring out what's wrong (it may look like noise to you and me, but be very meaningful to the experts.)

Thanks again for reporting this bug, since you've tested it on both ATI and nVidia it sounds like it could be a widespread issue.

[ricardisimo (ricardisimo)]

Here they come... will try to get the screenshot, although it didn't capture anything when I got hit with a mild case at work; the screen looked perfectly normal.

[ricardisimo (ricardisimo)]

Next...

[ricardisimo (ricardisimo)]

This probably doesn't bode well for me... the screenshot didn't capture any of the "noise" or displacement. My guess is that the most likely culprits, then, are my cheap monitors (Hansol, for example). Still, why is the problem only when logging out and back in on Ubuntu, and on two different systems with different cards? Oh, and I've discovered that "Switch User" avoids the problem altogether. Nevertheless, it might be worth investigating, no?

I will post the corresponding info from the other machine tonight or tomorrow. Thank you for your help.

[Bryce Harrington (bryce)]

Hi ricardisimo,

Have you had luck getting a good screenshot or photo from the other system so far?

A couple things I'd like to clarify:

First, does the corruption go away if you set your resolution to the same as the person you're changing from? I.e., does the problem depend on switching users with different resolutions, or does it occur for switching users at all? Does it happen both ways - if you switch from your high resolution setup to one of the two lower resolution ones, do you also see the corruption?

Second, does the corruption only occur on the X display, or does it also appear on the login screen?

Third, I notice in your xorg.conf you have this set:

  Option "UseFBDev" "true"

If that's set to "false" what happens? I notice in your Xorg.0.log file that it's hitting errors when trying to activate the framebuffer:

(II) Loading sub module "fbdevhw"
(II) LoadModule: "fbdevhw"
(II) Loading /usr/lib/xorg/modules/linux//libfbdevhw.so
(II) Module fbdevhw: vendor="X.Org Foundation"
 compiled for 7.2.0, module version = 0.0.2
 ABI class: X.Org Video Driver, version 1.1
(WW) open /dev/fb0: No such file or directory
(WW) open /dev/fb1: No such file or directory
(WW) open /dev/fb2: No such file or directory
(WW) open /dev/fb3: No such file or directory
(WW) open /dev/fb4: No such file or directory
(WW) open /dev/fb5: No such file or directory
(WW) open /dev/fb6: No such file or directory
(WW) open /dev/fb7: No such file or directory
(EE) Unable to find a valid framebuffer device
(EE) RADEON(0): Failed to open framebuffer device, consult warnings and/or errors above for possible reasons
 (you may have to look at the server log to see warnings)
(WW) RADEON(0): fbdevHWInit failed, not using framebuffer device

So that option isn't working. I'm guessing that disabiling it will have no substantial effect, but the corruption-when-switching sounds sort of frambufferish, so it's worth trying.

Fwiw, I doubt it has anything to do with your monitors. Since it occurs when logging out and back in, but not when doing Switch User, it makes me suspect something related to the login screen / framebuffer / gdm layer.

[ricardisimo (ricardisimo)]

Sorry for the delay. This comp has been lacking an internet connection for some time, and it's finally back.

Here are the corresponding files from this machine:
/etc/x11/xorg.conf

[ricardisimo (ricardisimo)]

/var/log/xorg.0.log

[ricardisimo (ricardisimo)]

And finally lspci -v
00:00.0 Host bridge: Silicon Integrated Systems [SiS] 661FX/M661FX/M661MX Host (rev 11)
        Flags: bus master, medium devsel, latency 32
        Memory at e0000000 (32-bit, non-prefetchable) [size=64M]
        Capabilities: [c0] AGP version 3.5

00:01.0 PCI bridge: Silicon Integrated Systems [SiS] SiS AGP Port (virtual PCI-to-PCI bridge) (prog-if 00 [Normal decode])
        Flags: bus master, 66MHz, fast devsel, latency 64
        Bus: primary=00, secondary=01, subordinate=01, sec-latency=64
        Memory behind bridge: dde00000-dfefffff
        Prefetchable memory behind bridge: cdd00000-ddcfffff

00:02.0 ISA bridge: Silicon Integrated Systems [SiS] SiS963 [MuTIOL Media IO] (rev 25)
        Flags: bus master, medium devsel, latency 0

00:02.1 SMBus: Silicon Integrated Systems [SiS] SiS961/2 SMBus Controller
        Flags: medium devsel
        I/O ports at 0c00 [size=32]

00:02.5 IDE interface: Silicon Integrated Systems [SiS] 5513 [IDE] (prog-if 80 [Master])
        Subsystem: Silicon Integrated Systems [SiS] SiS5513 EIDE Controller (A,B step)
        Flags: bus master, medium devsel, latency 128
        [virtual] Memory at 000001f0 (32-bit, non-prefetchable) [disabled] [size=8]
        [virtual] Memory at 000003f0 (type 3, non-prefetchable) [disabled] [size=1]
        [virtual] Memory at 00000170 (32-bit, non-prefetchable) [disabled] [size=8]
        [virtual] Memory at 00000370 (type 3, non-prefetchable) [disabled] [size=1]
        I/O ports at ffa0 [size=16]

00:02.7 Multimedia audio controller: Silicon Integrated Systems [SiS] AC'97 Sound Controller (rev a0)
        Subsystem: Elitegroup Computer Systems Unknown device a00b
        Flags: bus master, medium devsel, latency 64, IRQ 16
        I/O ports at e800 [size=256]
        I/O ports at ec00 [size=128]
        Capabilities: [48] Power Management version 2

00:03.0 USB Controller: Silicon Integrated Systems [SiS] USB 1.0 Controller (rev 0f) (prog-if 10 [OHCI])
        Subsystem: Silicon Integrated Systems [SiS] USB 1.0 Controller
        Flags: bus master, medium devsel, latency 64, IRQ 17
        Memory at dfffd000 (32-bit, non-prefetchable) [size=4K]

00:03.1 USB Controller: Silicon Integrated Systems [SiS] USB 1.0 Controller (rev 0f) (prog-if 10 [OHCI])
        Subsystem: Silicon Integrated Systems [SiS] USB 1.0 Controller
        Flags: bus master, medium devsel, latency 64, IRQ 18
        Memory at dfffe000 (32-bit, non-prefetchable) [size=4K]

00:03.3 USB Controller: Silicon Integrated Systems [SiS] USB 2.0 Controller (prog-if 20 [EHCI])
        Subsystem: Silicon Integrated Systems [SiS] USB 2.0 Controller
        Flags: bus master, medium devsel, latency 64, IRQ 19
        Memory at dffff000 (32-bit, non-prefetchable) [size=4K]
        Capabilities: [50] Power Management version 2

00:04.0 Ethernet controller: Silicon Integrated Systems [SiS] SiS900 PCI Fast Ethernet (rev 90)
        Subsystem: Silicon Integrated Systems [SiS] SiS900 10/100 Ethernet Adapter
        Flags: bus master, medium devsel, latency 64, IRQ 20
        I/O ports at e400 [size=256]
        Memory at dfffc000 (32-bit, non-prefetchable) [size=4K]
        Expansion ROM at dffc0000 ...

[ricardisimo (ricardisimo)]

To answer at least one of your questions, it does make a difference that the other user's screen res be different from mine, in two ways. Firstly, it makes that "noise" and displacement take place; secondly, the problem is more pronounced when the resolutions are further apart. So, when I log out of my son's 800*600 and log in to my 1280*1024, the screen is a mess (although not so bad here today, I must admit), whereas my wife's 1024*768 doesn't cause nearly the same distortion, and as I said before, I can "snap" the screen back into place my simply rolling my mouse pointer to the edge of the screen.

I will try modifying the framebuffer as per your suggestion, and will post back shortly. Thank you so very much for your attention to my problem.
Ricardo

[ricardisimo (ricardisimo)]

Bryce... OK... stoopid nooby question: Do I edit xorg.conf with "sudo gedit" or with "sudo dpkg-reconfigure xserver-xorg"? Or is it with something else? Thanks again.

[ricardisimo (ricardisimo)]

P.S. - Everyscreenshot I take looks completely normal, so it would appear to be happening somewhere after the graphics card, no?

[ricardisimo (ricardisimo)]

P.S. - Every screenshot I take looks completely normal, so it would appear to be happening somewhere after the graphics card, no?

[ricardisimo (ricardisimo)]

Sorry if this isn't the place to ask, but what does "triaged" mean? Also, once again, how do I edit xorg.conf? Thanks in advance.

[Bryce Harrington (bryce)]

Hi ricardisimo,

Yes you can edit xorg.conf with sudo gedit xorg.conf.

Since screenshots are not working out (this is not a surprise), do you have access to a digital camera? If so, just snap a photo of what you see. If not, I think you may have already provided sufficient data to investigate it.

"Triaged" is a new category. It means that the bug has been officially reviewed and has sufficient information that a developer can work on it.

[ricardisimo (ricardisimo)]

I'm very sorry this has taken me so long. I mistakenly thought that I had already uploaded this image, and I was wondering why no one was commenting on it.

This is the best I could do, sadly. Still, it should give you some idea of the sort of "noise" and displacement that takes place.

[Brian Murray (brian-murray)]

Thanks for taking the time to report this bug and helping to make Ubuntu better. In the development cycle for Intrepid there have been some vast improvements in the open source ati video driver and we could use your help testing them. Could you please download the latest Alpha CD image of Intrepid and test this particular bug just using the Live CD? You can find the latest image at http://www.ubuntu.com/testing . Your testing can help make Ubuntu and the open source ati driver even better! Thanks in advance.

[ricardisimo (ricardisimo)]

I'd love to help out, but my old motherboard with the ATI card in question had too many problems, so it's gone, Different video problems with the new onboard graphics, though... You might read about it elsewhere. Sorry.

[Bryce Harrington (bryce)]

Closing since hardware to troubleshoot the issue is no longer available.