Monday, July 14, 2008
Solved: the monitor/video card ass-pain
I am, however, a bit of an energy efficiency nut, which is why when I designed my "new" PC (now a couple years old) I chose a reasonably capable motherboard that had decent onboard video and sound and minimal power consumption. While I did eventually end up upgrading the sound card (the one on the board ultimately ended up being too noisy and always required DC offset adjustment), I have never had any desire to upgrade to an energy-hogging video card with 8 fans and its own power connector. I like my cool, 100-watt, quiet PC as it is.
Almost the entire time I've had this PC, however, I've been plagued by an irritating problem. If I turned off the Viewsonic vx2035wm monitor I had plugged into the Wintec ADD2 DVI card (one thing the Intel DG965OT board lacked was an on-board DVI connector) and turned it back on, the resolution changed from 1680x1050 to 1400x1050. Sometimes Windows would also change its idea of my monitor from the Viewsonic to the Default Monitor. No amount of BIOS upgrading or video driver updating or monitor driver updating seemed to make any difference.
Today I decided I wanted to rule out a problem with the Wintec ADD2 card, so I pulled the card and plugged the monitor into the analog VGA port. Of course this makes the video look quite ugly. What I found was that after installing the drivers for the monitor, it wasn't getting detected, and if I updated the driver to the Viewsonic one by hand, I wasn't able to even select the native resolution at all.
That led me to Intel's solution ID CS-028366. A problem with reading the EDID from some flat panel monitors with Intel's G965 video chipset leads the driver to fail to see the native resolution of the display. Intel cooked up a special driver for people experiencing this problem, which can be downloaded from the solution page. I updated to this driver, and that made it possible to select the native resolution for the display in analog mode.
This got me to wondering if misreading the EDID could cause the problem I had with the digital connector as well, so I powered down and reconnected the ADD2 card. After restarting I found that in fact, the native resolution of the monitor was selected each time if I turned off my monitor and turned it back on now. Problem solved, provided it doesn't randomly return as things sometimes do in the Windows XP world.
Intel doesn't provide much in the way of technical details about what causes the problem or what their fixed driver actually does, but we might be able to guess from their saying "there may be side effects to this solution such as longer than normal resume times from standby" that either they're requesting the EDID at a lower bit rate, they're requesting the EDID multiple times looking for matching data, or they're throwing in a short delay after waking up the monitor and before requesting the EDID (perhaps monitors with limited horsepower can only tackle one task at a time and the delay permits the monitor some time to finish starting up the display before having to answer an EDID request).
In any case, I'm glad I can finally turn my monitor off.
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