[CentOS] Strange dots on monitor

Mon Dec 18 00:18:27 UTC 2017
Valeri Galtsev <galtsev at kicp.uchicago.edu>

On Sun, December 17, 2017 4:26 pm, vychytraly . wrote:
> Yves thank you very much for your help, today I tried newer drivers but
> the
> problem persists. So I think it is hardware problem. Since the laptop is
> still in warranty I will probably contact the manufacturer. My only worry
> is that they would not accept it since I am running Linux (the laptop came
> with Windows - and I am not sure if the problem would be also present on
> Windows). Do you think there could be some issues with warranty service in
> this case?

To me it sounds like hardware problem. I can imagine that to happen if the
chip was overheated. I would check if the fan on video card is not stuck,
and if there are cables or anything that could get into fan and stop it.
This basically is about figuring out what happened.

If dots are periodic, and are of "clean" color (i.e. RGB or combination of
any pair of these at arbitrary intensities), then these look like trouble
with some bus drivers inside video chip related to internal data
interconnect. If you fry ATI video chip, the pattern is rather simple
(periodic). I have seen also periodic pattern on older nvidia cards after
they had been overheated. In my experience it is much easier to damage by
overheating nvidia based card than ATI based, but I have seen more or less
modern ATI card fried as well.

Warranty: I wouldn't worry about which system the machine was purchased
with and under which hardware failed. I've dealt with a lot of failed
hardware, and usually hardware vendors will not tell you that you damaged
their hardware because you run wrong system or wrong driver. If I were
told that by hardware manufacturer (which I never was), I will immediately
reply that if hardware was connected to bus resembling specs, no matter
what signals are sent to hardware, it will not be damaged. It it is
damaged because of that, then hardware was poorly designed from electrical
engineering point of view. And this is indeed true about all rather
trivial things such as computer components.

What hardware vendor is entitled for is: have "faulty" hardware tested
under the system the computer was sold with. That is: before even going to
warranty replacement, do the test with Windows, and confirm the failure.
They may ask you go through variety of steps they have in their diagnostic
schedule, follow what they tell, and report what you observe. They really
appreciate if you report what you tried when you start talking to them,
meaning that you put effort in solving it, but they will need
troubleshooting according to their procedures done as well.

Good luck.


> Thank you very much and have a nice day.
> On Sun, Dec 17, 2017 at 2:53 AM, Yves Bellefeuille <yan at storm.ca> wrote:
>> "vychytraly ." <vychytraly at gmail.com> wrote:
>> > I forgot to write that the dots start to appear only inside "Desktop
>> > Environment" (in my case Gnome), not for example in grub/bios. Today
>> > I tried to install ubuntu 16.04 and the green dots appeared there too
>> > (in Unity).
>> Video BIOS isn't the same as the usual video graphics:
>> https://en.wikipedia.org/wiki/Video_BIOS . I think that's still true
>> with UEFI.
>> In other words, I would suspect a hardware problem or a driver problem
>> rather than a software problem.
>> --
>> Yves Bellefeuille
>> <yan at storm.ca>
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Valeri Galtsev
Sr System Administrator
Department of Astronomy and Astrophysics
Kavli Institute for Cosmological Physics
University of Chicago
Phone: 773-702-4247