ATI FGLRX HDMI Underscan Problem [Solved]

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Adaemox
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ATI FGLRX HDMI Underscan Problem [Solved]

Post by Adaemox »

Edit: Got me an Nvidia gfx card! And wa-la no more underscan issues! :)

http://ohioloco.ubuntuforums.org/showth ... ?p=6615562

See link above for some further information as well as a hack fix. Since Linux Mint is AV orientated I was hoping some of you guys might be running a similar setup and have some additional words of wisdom in getting this to work properly.

An overview of the problem: With default ATI drivers (non-proprietary) the desktop and everything else fills the screen from left to right and top to bottom. No overscan and no underscan. Once I install the FGLRX drivers and reboot everything is displayed, at approximately 15% underscan. I estimate 15% because in windows this very same thing happens but in the ATI driver control panel there is a slider which you can adjust it to 0% underscan. I have attempted to fix this by using the configuration options on my TV and the limited options in the linux ATI driver control panel but no such luck.

Anyway, just seeing if anyone here has some further insight, short of that I'll likely run with the above hack until ATI gets their linux control panel up to speed with the Window's one.
Last edited by Adaemox on Thu Dec 24, 2009 12:41 am, edited 1 time in total.
Adaemox

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Husse
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Re: ATI FGLRX HDMI Underscan Problem

Post by Husse »

Anything to do with the different TV standards that are used - ntsc and pal and some others
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Lolo Uila
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Re: ATI FGLRX HDMI Underscan Problem

Post by Lolo Uila »

Unfortunately this is a problem with the newer ATI series cards (anything newer than the X800/850 series). I went back and forth with ATI Tech "Support" around 2 years ago and was finally told they had no fix and would let me know when they did. Later I got an email suggesting I try some newer driver that was supposedly fixed, but of course it was not.

I just gave up on the DVI-HDMI and started using the VGA port on my TV. Works great, and no over/underscan. Of course if you don't have a full resolution VGA port on your TV then you're out of luck.

The Problem:
The Radeon X1K (and newer) series cards ignore the "Use centered timings" setting and scale the image when outputting at 60Hz HD TV resolutions (720P/1080P).

This is definitely a hardware problem with the X1K series cards. How do I know? Because I can replace my X1950 Pro with my old X800 XT and the problem goes away. Same computer, same software, same drivers, same settings, and the X800 XT produces a properly centered, 1:1 pixel mapped, and very sharp display. While the X1950 upscales the 720P output and underscans the 1080P output resulting in a blurry image with large borders. This only happens at 1280x720 and 1920x1080 @ 60Hz. Other resolution settings produce a properly centered, 1:1 pixel mapped display.

I was messing with this stuff in both Linux and WinBlows back when the Cat drivers were early 7.xx versions, and I did find something interesting. The 7.1 version of the WinXP driver would allow me to set any refresh rate I wanted (others detected the display as a TV and would only allow 60Hz), and if I set my refresh higher than 60Hz the problem went away. Oddly the card still output 60Hz because the TV still detected a 1080p/60 signal, but just setting the driver to 75 (or 100 or anything higher) fixed the underscan and gave the proper output. From this it seemed clear that this issue can, in fact, be fixed in software.

I did report all this to ATI way back when, but it appears that the problem still exists. :( Oh well, my TV has a full rez VGA port, so I'm still :)
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Adaemox
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Re: ATI FGLRX HDMI Underscan Problem

Post by Adaemox »

Thanks Lolo Uila. I do have a VGA connection on my TV so I'll give that a go. I've heard the ATI drivers that are suppose to be out around time of Ubuntu's 9.04 release might have the scanning adjustment in the CCC that it does in Windows. Here's hoping for a fix sometime soon. :D
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