[CentOS] New monitor weirdnesses (CentOS 5.11)

Tue Dec 1 20:47:13 UTC 2015
Robert Heller <heller at deepsoft.com>

I just got a new monitor for my desktop system (the old one died after *many* 
years of service).  The new monitor is a high res 16:9 monitor, but the VESA video 
driver insists on using 1024x768 (which was the resolution of the *old* 
monitor).  It does seem to detect higher, 16:9 resolutions but it is not using 
them.  I *think* I need to set some low-level video mode thing, but it has 
been a long time since I have had to do that that I have totally forgotten how 
to do it.  And I have been unable to find it with a websearch either.

>From /var/log/Xorg.0.log:

(II) VESA(0): Printing DDC gathered Modelines:
(II) VESA(0): Modeline "1366x768"x0.0   85.50  1366 1436 1579 1792  768 771 774 798 +hsync +vsync (47.7 kHz)
(II) VESA(0): Modeline "1360x768"x0.0   85.50  1360 1424 1536 1792  768 771 777 795 +hsync +vsync (47.7 kHz)
(II) VESA(0): Modeline "800x600"x0.0   40.00  800 840 968 1056  600 601 605 628 +hsync +vsync (37.9 kHz)
(II) VESA(0): Modeline "800x600"x0.0   36.00  800 824 896 1024  600 601 603 625 +hsync +vsync (35.2 kHz)
(II) VESA(0): Modeline "640x480"x0.0   31.50  640 656 720 840  480 481 484 500 -hsync -vsync (37.5 kHz)
(II) VESA(0): Modeline "640x480"x0.0   31.50  640 664 704 832  480 489 492 520 -hsync -vsync (37.9 kHz)
(II) VESA(0): Modeline "640x480"x0.0   30.24  640 704 768 864  480 483 486 525 -hsync -vsync (35.0 kHz)
(II) VESA(0): Modeline "640x480"x0.0   25.18  640 656 752 800  480 490 492 525 -hsync -vsync (31.5 kHz)
(II) VESA(0): Modeline "720x400"x0.0   28.32  720 738 846 900  400 412 414 449 -hsync +vsync (31.5 kHz)
(II) VESA(0): Modeline "1024x768"x0.0   78.75  1024 1040 1136 1312  768 769 772 800 +hsync +vsync (60.0 kHz)
(II) VESA(0): Modeline "1024x768"x0.0   75.00  1024 1048 1184 1328  768 771 777 806 -hsync -vsync (56.5 kHz)
(II) VESA(0): Modeline "1024x768"x0.0   65.00  1024 1048 1184 1344  768 771 777 806 -hsync -vsync (48.4 kHz)
(II) VESA(0): Modeline "832x624"x0.0   57.28  832 864 928 1152  624 625 628 667 -hsync -vsync (49.7 kHz)
(II) VESA(0): Modeline "800x600"x0.0   49.50  800 816 896 1056  600 601 604 625 +hsync +vsync (46.9 kHz)
(II) VESA(0): Modeline "800x600"x0.0   50.00  800 856 976 1040  600 637 643 666 +hsync +vsync (48.1 kHz)
(II) VESA(0): Modeline "1280x720"x60.0   74.48  1280 1336 1472 1664  720 721 724 746 -hsync +vsync (44.8 kHz)
(II) VESA(0): Searching for matching VESA mode(s):

Any of 1360x768, 1366x768, or 1280x720 would be fine.

Following this are a pile of blocks starting with 'Mode: ...' or '*Mode: ...'.
I think these are the modes the driver is reading from some 'magic' place and
maybe the stared ones are 'matches' to the DCC mode lines. I think what I need
to do is update this 'magic' place with a low-level program (probably
eventually run in /etc/rc.local or someplace like that) that will add in a
'Mode' -- I did this *years* ago with little machines with Intel video chips 
and 16:9 monitors. But I am totally blanking on the command to use.  I find 
using a 4:3 video mode on a 16:9 monitor somewhat unusable.

I running CentOS 5.11 w/Xen. The video chipset is a NVIDIA Corporation C77
[GeForce 8200] (rev a2). I am using stock CentOS 5 drivers and libraries
(slightly out of date).


-- 
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