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Date:      Tue, 17 Mar 1998 18:05:36 +1030
From:      Greg Lehey <grog@lemis.com>
To:        Jonathan Lemon <jlemon@americantv.com>, "Dogbert's Nephew" <englishk@gwis2.circ.gwu.edu>
Cc:        questions@FreeBSD.ORG
Subject:   Re: X Resolution stuck at 320
Message-ID:  <19980317180536.15799@freebie.lemis.com>
In-Reply-To: <19980316222518.42157@right.PCS>; from Jonathan Lemon on Mon, Mar 16, 1998 at 10:25:18PM -0600
References:  <v04003a0cb133776276d5@[208.140.182.45]> <Pine.3.89.9803162220.A20438-0100000@gwis2.circ.gwu.edu> <19980316222518.42157@right.PCS>

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On Mon, 16 March 1998 at 22:25:18 -0600, Jonathan Lemon wrote:
> On Mar 03, 1998 at 10:29:51PM -0500, Dogbert's Nephew wrote:
>> Newbie here,
>>         sorry, i can't seem to figure this one out but why is my
>> resolution stuck at 320x200. I've seen stuff in the archieve about this
>> but never seen the answer.
>
> The answer is in your XFConfig file:
>
>> # This is a set of standard mode timings. Modes that are out of monitor spec
>> # are automatically deleted by the server (provided the HorizSync and
>> # VertRefresh lines are correct), [....]
>
> Your monitor sez:
>
>> Section "Monitor"
>>     HorizSync   31.5 - 50
>
> So it can only support up to a 50kHz hsync frequency, no more.

Right.  That should do for 1024x768 with a bit of flicker, though.

> Now, your modelines for 640x480 are:
>
>> # 640x480 @ 72 Hz, 36.5 kHz hsync
>> Modeline "640x480"     31.5   640  680  720  864   480  488  491  521
>> # 640x480 @ 75 Hz, 37.50 kHz hsync
>> ModeLine  "640x480"    31.5   640  656  720  840   480  481  484  500
>> # 640x480 @ 85 Hz, 43.27 kHz hsync
>> Modeline "640x400"     36     640  696  752  832   480  481  484  509
>> # 640x480 @ 100 Hz, 53.01 kHz hsync
>> Modeline "640x480"     45.8   640  672  768  864   480  488  494  530
>
> Obviously, only the first 3 are going to be valid for your your monitor.
> The last is above the maximum 50 for your monitor, so it gets removed,
> and you get lines like:
>
>> (--) SVGA: Mode "640x480" needs hsync freq of 53.01 kHz. Deleted.
>
>
> Now, your card sez:
>
>> Section "Device"
>>     Clocks  25.18
>
> Which means that it only supports a "dot clock" rate of 25.18.  Since
> the first 3 modelines require minimum dot clocks of 31.5, 31.5, and 36
> respectively, none of them are valid, and get thrown out.  Then, the
> system falls back to a builtin 320x200, which is probably within your
> device/monitor capabilities.
>
> If your video card really does support high res mode, then you will
> need to get a correct `Clocks' line for your card.  If not, then you
> might want to look at the `Doublescan' section of the modelines.

Nice analysis.  A couple of points:

This Clocks line is definitely wrong.  All VGAs can support a 28 MHz
dot clock as well.  Almost any modern board will offer a range of
other frequencies, though it can be a challenge to find them out.  

The original poster didn't say what kind of board he had, so there's
no way of being sure, but one possibility would be to comment out the
Modes line and see if the server can guess what clocks are available.
It's certainly easy enough to try, and it could solve the problem.

Greg


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