[Solved] another flickering monitor problem

falsum · 2011-06-04 09:09:35

Hi,

I hooked a new LED monitor to my laptop via a VGA cable but the sad
part is that the monitor flickers quite a bit. It's not a hardware
problem because I hooked the monitor to a windows box (using the same
VGA cable), and the monitor works perfectly well.

My laptop uses the video card ATI Radeon HD 3670. I'm currently using
the open source driver xf86-ati-video.

Here are a few things I've tried (many of them based from previous
posts) that I didn't have any success: to use the ATI's proprietary
driver (catalyst); to use xf86-ati-video-git; to disable KMS; to check
the output of xrandr (the preferred and the current mode match); and
to downgrade to older version of the xf86-ati-video. My archlinux box is
also upgraded.

I noticed the following patterns in my monitor flickering:

- it only happens with darker colors (no flicker when I open a white
page for instance).
- the flicker is not limited to X. The virtual consoles also flicker.
So I think that means that the cause of the flicker has nothing to
do with Xorg.
- the flicker is vertical.
- The flicker does not occur when I'm at the GRUB menu.

Any suggestion of how I can solve this problem is more than welcome!

Cheers,

Last edited by falsum (2011-06-05 00:39:10)

karol · 2011-06-04 09:50:55

Check your refresh rates (you should have some buttons on your monitor).
But that wouldn't explain why grub and light background are fine and you say the flicker is vertical ...

Can you use another connector or do you have only VGA on your laptop?

Last edited by karol (2011-06-04 09:55:04)

falsum · 2011-06-04 19:37:05

karol wrote:

Check your refresh rates (you should have some buttons on your monitor).
But that wouldn't explain why grub and light background are fine and you say the flicker is vertical ...
Can you use another connector or do you have only VGA on your laptop?

I didn't find buttons to change the refresh rates on my monitor but I used xrandr to change the refresh rates. In addition to 60, the preferred one (according to xrandr), I tried 59.8, 59.9, 70.1, 75, and 75.1. The flicker still continues though

About using another conector, VGA is my only option. The monitor also accepts DVI but my laptop doesn't have a port for that.

karol · 2011-06-04 19:51:16

Were you changing vertical or horizontal refresh rates?

falsum · 2011-06-04 20:49:28

karol wrote:

Were you changing vertical or horizontal refresh rates?

Oh, I didn't know that there was a difference between vertical and horizontal refresh rates. I changed the refresh rates using the command

 xrandr -s <resolution>@<refresh-rate>

I would then check the result running the command xrandr.

karol · 2011-06-04 20:51:57

http://en.wikipedia.org/wiki/Horizontal_scan_rate
This is just a sorry excuse for a guess, I have simply no idea what might be wrong.

falsum · 2011-06-05 00:38:48

@Karol: thanks so much for your help.

I finally solved the flickering problem. Since my laptop has a HDMI port, I bought a HDMI to DVI cable and the flickering is gone now. At the end, I guess the problem was the VGA port of my laptop.

karol · 2011-06-05 08:56:54

falsum wrote:

I guess the problem was the VGA port of my laptop.

I'm really glad you solved it :-)
If you want, you can boot a liveCD / liveUSB and see if it has problems with your VGA too. If it runs OK, the problems may be related to your Arch setup.
If you can get another monitor with a VGA connector you can test it too - maybe your laptop is just jealous of the new shiny monitor ;P

falsum · 2011-06-07 03:57:29

karol wrote:

falsum wrote:
I guess the problem was the VGA port of my laptop.
I'm really glad you solved it :-)
If you want, you can boot a liveCD / liveUSB and see if it has problems with your VGA too. If it runs OK, the problems may be related to your Arch setup.
If you can get another monitor with a VGA connector you can test it too - maybe your laptop is just jealous of the new shiny monitor ;P

These are good ideas. I get the same flickering with the ubuntu live cd but I didn't try with the arch live cd yet. As to other monitors, I still get the same flickering when I use a different monitor with a VGA cable.
I think you're right: my laptop must be getting jealous :-)

Arch Linux

#1 2011-06-04 09:09:35

[Solved] another flickering monitor problem

#2 2011-06-04 09:50:55

Re: [Solved] another flickering monitor problem

#3 2011-06-04 19:37:05

Re: [Solved] another flickering monitor problem

#4 2011-06-04 19:51:16

Re: [Solved] another flickering monitor problem

#5 2011-06-04 20:49:28

Re: [Solved] another flickering monitor problem

#6 2011-06-04 20:51:57

Re: [Solved] another flickering monitor problem

#7 2011-06-05 00:38:48

Re: [Solved] another flickering monitor problem

#8 2011-06-05 08:56:54

Re: [Solved] another flickering monitor problem

#9 2011-06-07 03:57:29

Re: [Solved] another flickering monitor problem

Board footer