Black dots/lines randomly appear on screen

[tyela]

I have installed Ubuntu 13.04 on a Toshiba Satellite U845-S409 a week ago. Starting yesterday, every once in a while, there is a pattern of short, horizontal black lines that appear over the whole screen, which lasts about a second and then dissapears. Any thoughts on that?

[papibe]

Hi tyela. Welcome to the forum

My first guess would be to check your graphic card and drivers.

Could you open a terminal, run this commands and post the results?

lspci -nnk | grep -iA2 vga

xrandr

xvidtune -show

lsmod | grep -iE 'nvidia|intel|fglrx|radeon|nouveau'

Regards.

[tyela]

Thanks! Here's what I get:

mon@eyvindur:~$ lspci -nnk | grep -iA2 vga
00:02.0 VGA compatible controller [0300]: Intel Corporation 3rd Gen Core processor Graphics Controller [8086:0166] (rev 09)
    Subsystem: Toshiba America Info Systems Device [1179:fba1]
    Kernel driver in use: i915
mon@eyvindur:~$ xrandr
Screen 0: minimum 320 x 200, current 1366 x 768, maximum 32767 x 32767
LVDS1 connected 1366x768+0+0 (normal left inverted right x axis y axis) 310mm x 174mm
   1366x768       60.0*+
   1360x768       59.8     60.0  
   1024x768       60.0  
   800x600        60.3     56.2  
   640x480        59.9  
VGA1 disconnected (normal left inverted right x axis y axis)
HDMI1 disconnected (normal left inverted right x axis y axis)
DP1 disconnected (normal left inverted right x axis y axis)
mon@eyvindur:~$ xvidtune -show
"1366x768"     69.30   1366 1398 1430 1470    768  771  776  786 -hsync -vsync

mon@eyvindur:~$ lsmod | grep -iE 'nvidia|intel|fglrx|radeon|nouveau'
kvm_intel             126842  0 
kvm                   376505  1 kvm_intel
aesni_intel            18156  2 
aes_i586               16995  1 aesni_intel
xts                    12749  1 aesni_intel
lrw                    13057  1 aesni_intel
ablk_helper            13357  1 aesni_intel
snd_hda_intel          38307  3 
snd_hda_codec         117580  3 snd_hda_codec_hdmi,snd_hda_codec_conexant,snd_hda_intel
snd_pcm                80890  3 snd_hda_codec_hdmi,snd_hda_codec,snd_hda_intel
snd_page_alloc         14230  2 snd_pcm,snd_hda_intel
snd                    56485  16 snd_hwdep,snd_timer,snd_hda_codec_hdmi,snd_hda_codec_conexant,snd_pcm,snd_seq,snd_rawmidi,snd_hda_codec,snd_hda_intel,snd_seq_device

[papibe]

Thanks.

So far, so good. You have Intel integrated graphics, and you are using the proper driver.

Let's see if there's something on the X log. Could you paste the content of this file?

/var/log/Xorg.0.log

Please paste it here: paste.ubuntu.com, and post back the link to it.

Regards.

[tyela]

http://paste.ubuntu.com/5700944/

[papibe]

Thanks.

There no graphic error reported on the log.

Let's check the version of your driver. Could you post the output of this command?

apt-cache policy xserver-xorg-video-intel

Regards.

[tyela]

Alright:

xserver-xorg-video-intel:
  Installed: 2:2.21.6-0ubuntu4
  Candidate: 2:2.21.6-0ubuntu4
  Version table:
 *** 2:2.21.6-0ubuntu4 0
        500 http://us.archive.ubuntu.com/ubuntu/ raring/main i386 Packages
        100 /var/lib/dpkg/status

[papibe]

It looks like everything is OK.

My only guess (not assuming hardware problems) would be that there's a flaw/bug on the 13.04 driver.

There's only one version upstream you can upgrade to, but it falls into the "experimental/unstable" category.

This would be the instructions to upgrade:

sudo add-apt-repository ppa:xorg-edgers/ppa

sudo apt-get update

sudo apt-get upgrade

You may need to reboot after that.

Let us know how it goes.
Regards.

[tyela]

Hi papibe,

I upgraded the driver and the problem has not manifested itself since then (it used to be pretty frequent), so I'm going to assume that this is solved for now. I hope I'm not speaking too fast.

In any case, thanks a lot for the help and for actually explaining what the instructions you're giving me are doing, it's much appreciated!

Cheers.

Alright, it seems that wishful thinking does not work and I have indeed spoken rashly. The problem is still there.

[tyela]

I was typing into terminal and the lines that appeared were now white instead of black. Also, they are more frequent when I do any kind of action. That is, they show up when I click something or give a command, rather than when the computer is idle. But it might be as small as moving the cursor... Not sure that's of any help.