Samsung LE40M86BD LCD HDTV problem
I recently bought a Mac Mini 1.83 GHz (Intel GMA 950 graphics) to use on my Samsung TV. A Windows XP PC with a Ati Radeon 9800 Pro has been used on it until now, connected with a DVI to HDMI cable. 720p works perfectly with this setup (with full 1:1 pixel mapping), but 1080p has never been tested due to the Radeon refusing to output a 1080p mode that the TV would accept (after many hours of PowerStrip tweaking I gave up and settled on 720p).
The Mac Mini on the other hand works with 1080p, but has display problems with both 720p and 1080p. I do not get 1:1 pixel mapping, evidenced by small black borders at the top, left and right side. Additionally there is a 1 pixel high horizontal green line near the top of the screen.
This is typical of timing problems, and changing the timings with SwitchResX confirms this since the green line can be changed to a vertical line on the left side with small adjustments.
Now for the interesting part. Using Monitor Asset Manager on Windows I dumped all information reported by the TV. Then I used PowerStrip to check the timings actually used for the 720p mode, and they matched what was reported as recommended settings for 720p by the Samsung TV.
Next I connected the Mac Mini to the TV and used SwitchResX to create a custom resolution with the exact same settings. After rebooting the result was the same. No 1:1 mapping, and the green line was still present.
I also tested VGA, which works perfectly in 1080p. I couldn't test 720p since the TV wouldn't accept that display mode over VGA (the Samsung specification claims it is unsupported over VGA but not over HDMI). Additionally the Mini was connected to a Samsung SyncMaster 172T LCD monitor to verify that the DVI port wasn't broken, and it worked fine.
Any comments on this? Is this a driver bug?
Message was edited by: Bjorn Ruud
The Mac Mini on the other hand works with 1080p, but has display problems with both 720p and 1080p. I do not get 1:1 pixel mapping, evidenced by small black borders at the top, left and right side. Additionally there is a 1 pixel high horizontal green line near the top of the screen.
This is typical of timing problems, and changing the timings with SwitchResX confirms this since the green line can be changed to a vertical line on the left side with small adjustments.
Now for the interesting part. Using Monitor Asset Manager on Windows I dumped all information reported by the TV. Then I used PowerStrip to check the timings actually used for the 720p mode, and they matched what was reported as recommended settings for 720p by the Samsung TV.
Next I connected the Mac Mini to the TV and used SwitchResX to create a custom resolution with the exact same settings. After rebooting the result was the same. No 1:1 mapping, and the green line was still present.
I also tested VGA, which works perfectly in 1080p. I couldn't test 720p since the TV wouldn't accept that display mode over VGA (the Samsung specification claims it is unsupported over VGA but not over HDMI). Additionally the Mini was connected to a Samsung SyncMaster 172T LCD monitor to verify that the DVI port wasn't broken, and it worked fine.
Any comments on this? Is this a driver bug?
Message was edited by: Bjorn Ruud
Mac Mini (Intel 1.83 GHz), Mac OS X (10.5.2)
