getting hsync and vsync for a monitor (RESOLVED)

Fred Krogh · Last edited by Fred Krogh on Thu Jan 29, 2015 2:36 pm; edited 1 time in total

I have a new monitor and I would like to get values for HorizSync and VertRefresh to put in xorg.conf. I have found xresprobe, but it is a .deb package, and seems to have some dependencies, which I'm concerned could cause conflicts. I've emerged read-edid, but evidently my monitor will not work with it. It says

NeddySeagoon · Posted: Wed Jan 28, 2015 6:17 pm Post subject:

Fred Krogh,

Fred Krogh · Posted: Wed Jan 28, 2015 8:37 pm Post subject:

The monitor/tv is a Vizio 50in 4K display, model P502ui-B1e. I have contacted Vizio. They say that can't provide that information, and ultimately I was not all that friendly with them. I have really made an effort to search the web, but no luck.
Is there something I might do to read-edid or the kernel, that might help? Thanks.

NeddySeagoon · Posted: Wed Jan 28, 2015 8:58 pm Post subject:

Fred Krogh,

Connect the display to your PC and let Xorg ask for the EDID data,
You need to try HDMI port 5 and another one.
Post both /var/log/Xorg.0.log files
I suspect it will lie to the PC then upscale the picture.

Unless yod have a very very new graphics card, your PC won't drive it at 3840x2160, nor in 1.07 Billion colours.
OK, Xorg can do 30 bit colour now but it breaks lots of things to only have a 2 bit Alpha channel.
I'm not aware of any 4k capable graphics cards yet.

If Xorg can't get EDID data it will run at 640x480, which will be really ugly. However, HDMI inputs are required to provide EDID data.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

Fred Krogh · Posted: Wed Jan 28, 2015 9:09 pm Post subject:

I just purchased a Gigabyte GeForce TTX 970 which is supposed to handle 3840 x 2160 at 60 Hz. Unfortunately that card did not fit in my current case. (It a a long sucker!) I'm about to move my motherboard, etc. to a case I just bought. I'm doing all that I can to have some confidence that this new setup will not damage the monitor / tv and even that is has a reasonable chance to work.

NeddySeagoon · Posted: Wed Jan 28, 2015 9:51 pm Post subject:

Fred Krogh,

I'm confident that the display will not be damaged by connecting it to your PC.
Its been many years since that was designed out. Even later CRT displays had overscan protection.

The display self destruction mechanism is not present in flat panels
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

Fred Krogh · Posted: Wed Jan 28, 2015 9:56 pm Post subject:

Thank you. That is a bit of relief. I just connected by current system with an hdmi cable. First time I've tried this. The usual desktop fonts are huge, so huge that things are unreadable. Why would changing to use an hdmi connection have such an effect, and what might be done about it? Any ideas? Thanks,
Fred

NeddySeagoon · Posted: Wed Jan 28, 2015 10:23 pm Post subject:

Fred Krogh,

Post your /var/log/Xorg.0.log, lets see what Xorg did.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

Fred Krogh · Posted: Wed Jan 28, 2015 10:30 pm Post subject:

Fred Krogh · Posted: Wed Jan 28, 2015 10:42 pm Post subject:

Just in case it might prove useful, here is ~/.xsession-errors:

NeddySeagoon · Posted: Wed Jan 28, 2015 11:00 pm Post subject:

Fred Krogh,

That must have been ugly!

It wanted to do 1920x1080 but the EDID data looks to be broken, so it will have run at 640x480.
You will need to write a modeline and use the nvida option(s) to ignore some or all of the EDID data.

That post is 9 years old and uses a 4:3 aspect ratio mode as a worked example.

If you connect the PC to a 1920x1080 display, the Xorg.0.log should contain all the numbers you need for a modeline.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

Fred Krogh · Posted: Wed Jan 28, 2015 11:09 pm Post subject:

Yes, it is pretty high on the ugly scale. I'll have a close look at your link later. Thanks.

Fred Krogh · Posted: Thu Jan 29, 2015 3:43 am Post subject:

I was not able to get modeline generated as suggested in your link to work. But a little work on my kernel, and I now have output from get-edid|parse-edid

dweezil-n0xad · Posted: Thu Jan 29, 2015 10:28 am Post subject:

Fred Krogh · Posted: Thu Jan 29, 2015 2:35 pm Post subject:

Tried these options, and X would not start. BUT!!! with just the first one I have things working as they should. It's nice to have a usable desktop back. Many thanks.

I should have noted earlier that to get get-edid working, I [/quote]changed