ATI Catalyst 11.12 - black bars centered timings

[Kasreyn]

I have a monitor resolution issue upgrading to AMD Catalyst 11.12 (8.88.5.4) (from "Microsoft" WDDM v.120 (8.86.2.3)). The native resolution is shown with black bars at the top and bottom of the screen. Filling the screen is no longer possible without using stretch.

The monitor is a 26PF9946 with an optimal resolution of 1280x768. Maximum reported resolution is 1280x1024. Recommended resolution for the old driver was 1280x768 but is now somehow changed to 1280x1024. I've tried fiddling with the TVs settings, it has a 4:3 or 16:9 switch but nothing that helps. I feel this is really not the TVs fault as it works fine with the old driver (or my old Nvidia GPU).

I realize this monitor is getting really old and is not suitable for most tasks but, it it's decent enough for morning news webpage and a cup of tea

"Centered Timings" should give the correct 1:1 pixelmapping with sharp looking fonts. Rolling back to the old driver, the entire screen is filled and I'm guessing it's not using scaling to do it.

How can it not be possible to achieve the same thing using new drivers!?

Any suggestions to what might be done?

 

[KingFatty]

I think you still have some options to try. You could edit the driver settings, something like this but not so drastic: http://forums.entechtaiwan.com/index.php?topic=5984.0

Instead, maybe use the tools mentioned in that link to ensure that your new software drivers provide the options that correspond to the settings natively supported by the hardware.

I used this trick to get my monitor to accept resolutions that previously were not available under the drivers/settings, the new options just showed up under the settings area for resolution.

 

[Kasreyn]

You could edit the driver settings, something like this but not so drastic: http://forums.entechtaiwan.com/index.php?topic=5984.0

Thanks, I'm currently looking into EDID override using monitor driver.

I made some progress and set it 1280x960 instead of 1280x1024, this makes the black bars much smaller.

The 1280x768 resolution I want should be a 5:3 resolution as shown on this map from wikipedia:

The progress I had involves changing the aspect ratio from 4:3 to 16:10 in "Phoenix EDID editor" tool. I exported it from there and made a custom *.inf "monitor driver" (based on the example in this article http://msdn.microsoft.com/en-us/windows/hardware/gg487330)

Having read up on possible bits you can set in EDID binary data (http://en.wikipedia.org/wiki/Extended_display_identification_data) some aspect ratios seems to be missing. Assuming aspect ratio is how the height is determined there is "no need" to enter absolute values. If this is true EDID is either poorly designed or beyond me.

Possible values for bits 7-6 starting from byte 38 (of 8 possible grouped by 2bytes):

From http://en.wikipedia.org/wiki/Extended_display_identification_data :

00=16:10
01=4:3
10=5:4
11=16:9.
(Versions prior to 1.3 defined 00 as 1:1.)

Question is, what do you do when you want 5:3 ?

 

[Kasreyn]

I think the answer to how 5:3 is possible is by using EDID "Detailed Timings". There you can specify "Vertical Active Lines".

I found my timings from reading out the existing EDID from registry, I got the same result reading directly from the monitor. And from what I can tell it's correct, yet the mode refuses to show up in monitor settings.

In Phoenix I also checked "Preferred timing mode" which has the tooltip:

"The Display's Preferred Timing Mode is indicated in the First Detailed Timing Block (required for EDID v1 r3 and higher)"

Making a custom driver with that ticked didn't help though, the mode is now missing from monitor settings.

I have no idea what is appropriate for "H Blank", "H Sync Offset", "H Sync Width" and so on.

 

[Kasreyn]

I have come to the conclusion this is a driver issue. I think AMD/ATI Catalyst 11.12 doesn't read, interprets, or simply ignores the detailed timings from EDID. I base that on the fact that changes to standard timings does have an effect, where possible aspects are 16:9, 16:10, 4:3, 5:4.

I get it how this is not a problem on modern panels, they natively run one of the above mentioned aspects.

Short answer, if you want 5:3 native resolution, switch to nvidia (or run the outdated driver (8.86.2.3) where it actually works).

 

[n7]

Hmm, that's unfortunate for users of less common resolutions. :\