i810 vs. intel: frequency differences?

[Tom London]

On 4/13/07, Adam Jackson <ajackson at redhat.com> wrote:
> On Fri, 2007-04-13 at 10:37 -0700, Tom London wrote:
> > On 4/13/07, Adam Jackson <ajackson at redhat.com> wrote:
> > > On Fri, 2007-04-13 at 09:39 -0700, Tom London wrote:
> > > > Running xorg-x11-drv-i810-1.6.5-19.fc7, I've noticed that seem to
> > > > drive different monitor frequencies for the same
> > > > monitor/settings/xorg.conf.
> > > >
> > > > Running on two different LCD monitors, if my xorg.conf says 'i810', I
> > > > consistently get Horiz rate of 79.8kHz and Vert rate of 74.6Hz.
> > > >
> > > > If I only change i810->intel and restart X, I consistently get Horiz
> > > > rate of 83.0kHz and Vert rate of 77.8Hz (the last is above supported
> > > > rate (~75Hz) for both monitors).
> > >
> > > The X log, at least for the intel run, should show the exact timings
> > > being sent to the monitor, as well as what the monitor reports for
> > > capabilities.  That said, there could easily be bugs in the intel
> > > driver.
> > >
> > > > I've also noticed inconsistencies between the rates reported by my
> > > > monitors and that reported by xrandr when I run with 'intel': xrandr
> > > > reports Horiz is 80kHz (vs. monitor reporting 83kHz) and Vert is 75Hz
> > > > (vs. monitor reporting 77.8Hz).
> > >
> > > Rounding error.  Monitors are not particularly smart.
> > >
> > > - ajax
> > >
> > Would normally agree about 'rounding error', but setting the driver to
> > 'intel' puts 2 monitors 'out of range' for Horiz.  Also, the monitors
> > have no problem reporting 74.6 for 'i810' vs. 77.8 for 'intel'.  There
> > must be a difference in the actual signal.  No?
> >
> > What exactly from Xorg.0.log would be useful for me to provide?
>
> The whole thing, in a bug report, preferably.
>
> - ajax
>
BZ: https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=236414

Attached 3 copies of Xorg.0.log:
First right after graphical login running with 'intel', monitor is
'out of range' (77.8Hz).
Second above, plus ran 'xrandr --rate 60': monitor stabilizes
Third, changed xorg.conf to 'i810': running with 75 Hz (monitor agrees).

thanks in advance.....

tom
-- 
Tom London