vesa driver reports many modes, but only allows a few
ross at biostat.ucsf.edu
Mon Mar 1 12:35:30 PST 2010
On Mon, 2010-03-01 at 14:40 -0500, Adam Jackson wrote:
> On Sun, 2010-02-28 at 23:28 -0800, Ross Boylan wrote:
> > Could anyone explain to me what the attached log means?
> > X 7.5 detects a rich array of BIOS modes, but then runs through a list
> > of modes and says "no mode of this name". Should it be using something
> > like "104" or "104 (1024x768)" instead of, e.g., "1024x768"? Then X
> > tries a less strict probe, and rejects all but a couple of
> > low-resolution modes with "hsync out of range". I have no xorg.conf
> > file.
> The vesa driver attempts to find the intersection of the list of modes
> in the BIOS with the list of modes from EDID. You don't have an EDID,
> so this (unsurprisingly) gives you no modes.
> If we get to this point, we attempt to validate the BIOS mode list
> against the sync ranges configured for the monitor in xorg.conf, or from
> the defaults if there's no explicit configuration. That's what the
> "trying less strict filter" bit means. The default sync ranges for your
> server appear to be just big enough for 800x600.
> If you want bigger modes, configure a bigger sync range:
> # big enough for 1600x1200 @ 60Hz
> Section "Monitor"
> Identifier "Monitor0"
> HorizSync 31.5 - 75.0
> VertRefresh 56.0 - 61.0
I tried an xorg.conf that had *only* the previous Monitor section. It
didn't seem to get hooked up to anything else. I also tried giving it
an identifier of "<default monitor>" since the log indicated that was
the monitor being used. In either case, I got
(==) Using config file: "/etc/X11/xorg.conf"
(==) No Layout section. Using the first Screen section.
(==) No screen section available. Using defaults.
(**) |-->Screen "Default Screen Section" (0)
(**) | |-->Monitor "<default monitor>"
(==) No monitor specified for screen "Default Screen Section".
Using a default monitor configuration.
Do I need to create a complete xorg.conf?
> Use the gtf(1) utility to calculate the upper bounds for sync ranges for
> the resolution you want:
> % gtf 1600 1200 60
> # 1600x1200 @ 60.00 Hz (GTF) hsync: 74.52 kHz; pclk: 160.96 MHz
> Modeline "1600x1200_60.00" 160.96 1600 1704 1880 2160 1200 1201 1204 1242 -HSync +Vsync
> - ajax
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