Samsung Syncmaster 204B [R] on DVI - don't try that at home!
Note: This instruction is valid for the ATI driver included with Ubuntu Feisty Fawn (7.04). There's another entry on how to get it working in Ubuntu Gutsy (7.10).
I recently decided that it was time to replace my old trustworthy Nokia Multigraph 446XPro CRT display with a flatscreen. The 446XPro has server me well at various computers at home since 1998 (that's eight years!) but it was time for something less space-consuming on my desk. Also, I like the feeling of not sitting in front of an electron beam several hours a day.My list of specifications for the replacement was rather short:
- Must handle a resolution of 1600x1200 (I've been working with this resolution for many hours a day for the past 8 years, so I'm quite used to it)
- Adjustable height
- Reasonable price
I got the screen just a few days after ordering it, and connected it to my graphics card, a ATI Radeon 9200SE, via analog VGA. After adjusting the vertical refresh to the recommended 60Hz, I got the display working, but with some distortions which made it hard to work with given the high resolution and the small font I use for displaying information. This was a disappointment. Obviously, the VGA decoder in the screen is not good enough to handle the recommended solution.
As a colleague of mine had similar trouble at work and solved them by switching to a graphics card with DVI output, I decided to go the easy way and buy a new graphics card, as the graphics card I had lacked DVI output. It turned out that the 9200SE was the very last card in the series that only had analog VGA output. My usual luck with hardware..
I bought a ATI Radeon 9250 as replacement and installed it. This gave me a sharp image. Yay! Or so I thought, because now, the screen started to go blank now and then with irregular intervals. It went completely black and then came back after half a second or so. Boy, that's irritating!
After many attempts, I managed to find the right words that made Google lead me right. This forum article led me to this forum article which describes the problem - it's a bug in the DVI implementation of Syncmaster 204B [R]. It can't handle the bandwidth. Gah! My usual luck with hardware..
The forum articles says this bug appears only on Syncmaster 204B [R], and only on models made in China. The latter seems not to be true, as mine is made in Slovakia.
There's a workaround - by lowering the vertical refresh to 56Hz, the problem goes away.
I'll do what I can to get a new screen without this bug anyway.
Here's my xorg.conf I use with the Radeon 9250 and the Syncmaster.