how to override max allowed dotclock ?

how to override max allowed dotclock ?

Post by Frank Gock » Wed, 19 Aug 1998 04:00:00



XFree86 Version 3.3 / X Window System
(protocol Version 11, revision 0, vendor release 6300)
Release Date: Jun  2 1997
Operating System: Linux 2.0.29 i586 [ELF]
Configured drivers:
  S3: accelerated server for S3 graphics adaptors (Patchlevel 0)
      newmmio, mmio_928, s3_generic

(--) S3: Ramdac type: s3_trio64
(--) S3: Ramdac speed: 135 MHz
(--) S3: Using Trio32/64 programmable clock (MCLK 59.957 MHz)
(--) S3: Maximum allowed dot-clock: 80.000 MHz
                              ^^^^^^^^^^^^^^^^^

In 16 bpp modes the X server just limits the dot clock to 80MHz which
results in bad refresh rates at high resolution. How can I tell my X
server to use higher dot clock ? I couldn't find a hint in the documentation
of X (it just tells there are some safe default limits but doesn't tell
how to customize them). I tried, very carefully :), to specify a higher dac
speed but it didn't change that limit.

TIA,
  Frank

 
 
 

how to override max allowed dotclock ?

Post by koen Gadey » Thu, 20 Aug 1998 04:00:00



Quote:>XFree86 Version 3.3 / X Window System
>(protocol Version 11, revision 0, vendor release 6300)
>Release Date: Jun  2 1997
>Operating System: Linux 2.0.29 i586 [ELF]
>Configured drivers:
>  S3: accelerated server for S3 graphics adaptors (Patchlevel 0)
>      newmmio, mmio_928, s3_generic

>(--) S3: Ramdac type: s3_trio64
>(--) S3: Ramdac speed: 135 MHz
>(--) S3: Using Trio32/64 programmable clock (MCLK 59.957 MHz)
>(--) S3: Maximum allowed dot-clock: 80.000 MHz
>                              ^^^^^^^^^^^^^^^^^

>In 16 bpp modes the X server just limits the dot clock to 80MHz which
>results in bad refresh rates at high resolution. How can I tell my X
>server to use higher dot clock ? I couldn't find a hint in the documentation
>of X (it just tells there are some safe default limits but doesn't tell
>how to customize them). I tried, very carefully :), to specify a higher dac
>speed but it didn't change that limit.

You need a newer version of XFree86 first, and then you can add

dacspeed a b c d

where a, b, c and d are the maximum dacspeeds for 8, 15, 24 and 32 bpp resp.

Note that overriding the default safe limits overrides the SAFE limits! You
may crash you machine, burn your card, fry your monitor, or even send out so
much radiation that a bunch of aliens comes to see who called them.

XFree86 is not going to be held responsible.

K.

Any oppinions expressed are my personal ones, and not those of my employer.

When replying, please remove all the numbers from the E-mail address.
This inconvenience is brought to you by Spamford and his E-mail vultures.

 
 
 

1. is the max dotclock of ET4000 card in IBM/VP 65Mhz????

Dear Linuxers,

At this moment I have X runnning on my IBM ValuePoint (DX2,6384-W5A) in
resolution 1024x768; I use a dotclock of 65 MhZ, i.e. a refresh rate of
60 Hz. According to the specs of my IBM monitor (6314-002) a refresh rate
of 70 Hz should be possible. However, I need a dotclock of 72 Mhz for
that and according to X the maximal dotclock of my Tseng ET4000 card is 65
Mhz.

To illustrate, this is the (partial) output of startx
(--) VGA256: ET4000: Initial hibit state: low
(--) VGA256: chipset:  et4000
(--) VGA256: videoram: 1024k
(--) VGA256: clocks:  25.20  28.32  32.70  36.30  40.30  45.00  50.30  65.40
(--) VGA256: clocks:  12.60  14.20  16.30  18.20  20.20  22.50   0.00   0.00
(--) VGA256: Maximum allowed dot-clock: 90MHz

It seeems to me that the second line is not OK, and moreover that XFree
is not capable to identify the second line of clocks properly.
I experienced a bit with option "hibit_high" in the Xconfig file, but
that did not help!

Are there any X/Linux/IBM-VP wizzard out there who know how let XFree access
higer dotclocks than 65 MhZ?

Frans

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