[Intel-gfx] Problems configuring unique xorg.conf file

[Alan W. Irwin]

On 2010-08-26 18:40-0000 Nasa wrote:

>
> ----- "Alan W. Irwin" <irwin at beluga.phys.uvic.ca> wrote:
>> [...]I have assumed above that the horizontal frequency limits have been
>> set correctly for your particular monitor.  That is not always the
>> case.  Check your monitor manual for the correct vertical and
>> horizontal frequency limits and if your X log shows those are not
>> being discovered properly by X than specify the correct ranges using
>> the
>> VertRefresh and HorizSync values in the Monitor section.  In my case
>> I used
>>
>> HorizSync       30-96
>> VertRefresh     48-120
>>
>> corresponding to values published in my Sony g200 manual, but your
>> monitor manual is very likely to require different ranges.
>>
>> Alan
>
> There in lies the problem....  I have created an xorg.conf file with
> the settings you mention -- but the settings are ignored.  Trying to
> tell Xorg not to use EDID/DDC/Default values hasn't worked (see 1st
> part of my orignal message).  Worse off, the log file doesn't report
> what values it is using!  So it's been a guessing game...

Look through the log file for the "ranges" string.  For my modern (LCD
monitor on Debian testing) system the result is

(II) intel(0): Ranges: V min: 55 V max: 75 Hz, H min: 30 H max: 80
kHz, PixClock max 140 MHz

(II) intel(0): Using hsync ranges from config file
(II) intel(0): Using vrefresh ranges from config file

However, despite those messages, it turns out HorizSync (and probably
VertRefresh) in my xorg.conf are ignored, and instead the values
reported by the monitor are used. (The above values are consistent
with those reported on the web for my particular monitor.  I set those
same values using HorizSync and VertRefresh except that I specified a
smaller H max via HorizSync as an experiment and it was ignored.)

Ignoring the frequencies in xorg.conf didn't hurt in my modern
LCD/Debian testing case, but probably does in yours.  To confirm
that what is the exact result you get for Ranges in the log file?

In general, I am troubled by any misguided tendency of Intel
developers to remove xorg.conf capability.  Sure, it is nice to
generally not require that file at all by default, but when you really
need control for situations where bad values or no values are being
reported by a monitor, a fully capable xorg.conf file is absolutely
essential.  So let's hope this ignoring of frequencies specified in
xorg.conf (at least for my Debian testing Intel X stack)
is a temporary aberration by the Intel developers that has been fixed
in later versions.

Alan
__________________________
Alan W. Irwin

Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).

Programming affiliations with the FreeEOS equation-of-state implementation
for stellar interiors (freeeos.sf.net); PLplot scientific plotting software
package (plplot.org); the libLASi project (unifont.org/lasi); the Loads of
Linux Links project (loll.sf.net); and the Linux Brochure Project
(lbproject.sf.net).
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