Arch Linux

webmonkey

Member

Registered: 2014-06-14

Posts: 2

[SOLVED (ish)] Red dot noise on screen - Intel Graphics

Hi all,

I am seeing "red dot noise" all over the screen, but only over some windows/apps (possibly those 3d rendered). Most noticeable on Plex, but also on LXDE desktop wallpaper. There is no noise during boot, over a terminal window (LCTerminal) or file manager (PCManFM).

If I take a screenshot (https://docs.google.com/file/d/0BytCytk … haaGc/edit) there is no noise, but on the actual screen (photo: https://docs.google.com/file/d/0BytCytk … wxY0E/edit) there is a lot.

I am using an Intel NUC (D34010WYK) with HD 4400 graphics.

lspci says:

00:02.0 VGA compatible controller: Intel Corporation Haswell-ULT Integrated Graphics Controller (rev 09)
	Subsystem: Intel Corporation Device 2054
	Kernel driver in use: i915
	Kernel modules: i915

Other details:

[root@mirwen-htpc ~]# lsmod | grep "kms\|drm"
drm_kms_helper         35720  1 i915
drm                   242043  5 i915,drm_kms_helper
i2c_core               25400  7 drm,i915,i2c_i801,i2c_hid,i2c_designware_platform,drm_kms_helper,i2c_algo_bit
[root@mirwen-htpc ~]# grep LoadModule /var/log/Xorg.0.log
[    12.551] (II) LoadModule: "dri2"
[    12.551] (II) LoadModule: "glamoregl"
[    12.631] (II) LoadModule: "glx"
[    12.635] (II) LoadModule: "intel"
[    12.640] (II) LoadModule: "modesetting"
[    12.641] (II) LoadModule: "fbdev"
[    12.642] (II) LoadModule: "vesa"
[    12.647] (II) LoadModule: "fbdevhw"
[    12.650] (II) LoadModule: "dri2"
[    12.872] (II) LoadModule: "evdev"

I am at a loss on how to debug this further or fix it, any help would be greatly appreciated!

Thanks

p.s. I checked the wiki "Intel Graphics" page and none of the troubleshooting issues seem to apply

Last edited by webmonkey (2014-06-14 14:43:22)

Head_on_a_Stick

Member

From: The Wirral

Registered: 2014-02-20

Posts: 8,999

Website

Re: [SOLVED (ish)] Red dot noise on screen - Intel Graphics

Hello webmonkey, welcome to Arch
If the "noise" is showing up on the screen but not the sceenshot, it seems to suggest a hardware related problem --- try fiddling with the settings on your monitor...
The stippled areas seem to be in the dithered sections of the screen and not in the sections showing plain colours: maybe a colour depth issue?

---

Jin, Jîyan, Azadî

webmonkey

Member

Registered: 2014-06-14

Posts: 2

Re: [SOLVED (ish)] Red dot noise on screen - Intel Graphics

Hi Head_on_a_Stick, Thanks for your swift response!

The problem is now "fixed" by plugging it directly into the TV, rather than via the amp (which works perfectly well for other devices).

I would still be very interested to understand why it doesn't work through the amp, when other devices do (implying the amp works okay) and it is fine when directly connected (implying the pc is okay). Strange.

Thanks for solving it though!

rune0077

Member

Registered: 2009-04-11

Posts: 135

Re: [SOLVED (ish)] Red dot noise on screen - Intel Graphics

I don't really now what your "amp" is, but I'm assuming it's some kind of intermediate device between your graphics card and your monitor/tv. If it works fine without this, then it's almost certainly something to do with that connection. If the amp works fine with other devices, are you using the exact same cables with those other devices?

If no, then the problem is likely the cable.

If yes, then the problem could still be the cable connection, because it could attach more firmly to those other devices. Try wiggling it gently where it connects to the graphics card and see if that has any effect on the dots. Make sure it's inserted firmly. (yes, we are still talking about hardware here, get your minds out of the gutter people :-) )