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nadman10

Member

From: USA

Registered: 2005-10-15

Posts: 202

Issues with AMD 6670 Dual Screens with open source drivers

I recently installed an AMD 6670 in my system to upgrade from my nvidia 8400. Since this "upgrade", I have had issues with my dual monitor setup. My second monitor is an Acer AL1916W that has given me nothing but problems from the start. When I try to enable it as a second monitor, it flickers back and forth constantly between solid black and yellow colors(enough to give you a seizure). I've added in my own modelines and it still does not work. I was able to get it working with the proprietary driver, however the 2D acceleration was unacceptable with that driver. Any ideas on where to start looking? I can't seem to find anyone else with this exact problem.

jacobopantoja

Member

From: Madrid

Registered: 2011-03-16

Posts: 44

Re: Issues with AMD 6670 Dual Screens with open source drivers

Is it working on console? Is your 2nd monitor working if connected alone? What connections are used for each monitors? Are the EDID data read from both monitors correctly?

Try with an absolutely clean xorg.conf and the stock xorg.conf.d files if it only occurs on Xorg

Please post a bit more of information which will improve the advice.

nadman10

Member

From: USA

Registered: 2005-10-15

Posts: 202

Re: Issues with AMD 6670 Dual Screens with open source drivers

Yes, the second monitor works in the console and works alone. Like I said, I had it working with the proprietary driver. The main monitor is DVI, while the one that isn't working is connected through VGA. I have had major EDID issues with the VGA monitor with both nVidia and AMD cards. So I guess the answer would be no, EDID is not read correctly on that monitor. I removed the 10-monitor.conf, however that did not seem to affect the issue at all.

jacobopantoja

Member

From: Madrid

Registered: 2011-03-16

Posts: 44

Re: Issues with AMD 6670 Dual Screens with open source drivers

At first we should try to know if the problem is with KMS or with Xorg.

If you are getting the native resolution for your Acer 2nd monitor IN GETTYs out-of-the-box, then it is clear that the problem is in Xorg. For that purpose, boot without any "video=" or "drm_kms_helper=" parameters in your kernel command line.

If you are not getting the native resolution on gettys, then do some debugging to see where the problem is.

$ cat /sys/class/drm/card0-VGA-1/edid > edid.bin
$ stat -c %s edid.bin

If it is 0, your monitor is not giving any EDID data (or it is not being correctly retrieved from your card). Try the same monitor in a different PC (different Graphic card).

If it is 128 or 256, your EDID may have a problem. Do

$ cat /sys/class/drm/card0-VGA-1/modes

and check whether the native resolution is listed or not (most likely not). If it is listed, I don't know what the problem is.

If it is not listed, then try to obtain the EDID of your monitor (e.g. by navigating through the windows drivers of your monitor, sometimes EDID is embedded) and follow the instructions in the wiki to force an edid file on KMS article

If KMS is finally working OK for your 2nd monitor, delete any xorg.conf file that you have and make sure that you only have the stock files under /etc/xorg.conf.d (you may e.g. check with pacman -Qo for each file under that directory, delete each file and reinstalling the proper package). Then Xorg should get the native resolution from the EDID data. If it doesn't work it's probably a bug in the Xorg driver for your board, try with a different graphics card.

nadman10

Member

From: USA

Registered: 2005-10-15

Posts: 202

Re: Issues with AMD 6670 Dual Screens with open source drivers

It was 0. This monitor has given me tons of EDID issues with nVidia and AMD cards. It's simply a pile of junk. I've searched high and low for EDID data on this and found none. Previously, I've had to manually add modelines with xrandr to get it to work properly, although, that hasn't worked in this instance.

I tried booting with the "nomodeset" option in the kernel line. This gave me a duplicated screen on both monitors, however, my main screen was limited to 1024x768 and arandr only saw the DVI port.