Difference in clock MHz between X Server 1.5.2 & X.Org X Server 1.9.4

[Adam Jackson]

On 2/25/11 10:32 AM, SD wrote:
> Dear All.
>
> I have ONE laptop with ONE hdd and 2 OS opensuse and fedora on it.
> When I boot opensuse LCD picture is perfect but is not on fedora.
> I spent many time to find differences and want to show you all this one:

You're conflating unrelated things:

> X.Org X Server 1.5.2
> Release Date: 10 October 2008
> X Protocol Version 11, Revision 0
> Build Operating System: openSUSE SUSE LINUX
> Current Operating System: Linux linux-xmc2 2.6.27.45-0.1-pae #1 SMP 2010-02-22 16:49:47 +0100 i686
> ...
> (II) intel(0): using SSC reference clock of 96 MHz

This is the spread spectrum reference clock, which is a property of the 
wiring of a given motherboard and is used to reduce EMI from the display 
connection.

> X.Org X Server 1.9.4
> Release Date: 2011-02-04
> [    22.536] X Protocol Version 11, Revision 0
> [    22.536] Build Operating System: x86-06 2.6.32-71.14.1.el6.x86_64
> [    22.536] Current Operating System: Linux f14.fedora14 2.6.35.11-83.fc14.i686.PAE #1 SMP Mon Feb 7 06:57:55 UTC 2011 i686
> ...
> [   135.556] (II) intel(0): Supported detailed timing:
> [   135.556] (II) intel(0): clock: 65.0 MHz   Image Size:  304 x 228 mm

This is the pixel clock of the preferred mode of the display.

Now, one or more of two things could be going wrong here.  Either the 
two OSes are detecting different SSC reference clocks, or they're 
picking display modes with different pixel clocks.  Either one could 
cause the display to look less than optimal.  But it's impossible to 
know without more log details.

intel-gfx@ is perhaps a better list for this kind of question.

- ajax