[Intel-gfx] [PATCH] honor VBIOS SSC & TV settings
wyskas at gmail.com
Tue Jul 1 02:10:17 PDT 2008
I'm getting the "(II) intel(0): using SSC reference clock of 96 MHz"
line in my Xorg.log with external CRT connected, but since I'm not
sure what exactly is this supposed to do, I can only say that it
didn't break anything :)
On Thu, Jun 26, 2008 at 6:36 PM, Jesse Barnes <jbarnes at virtuousgeek.org> wrote:
> I've been doing some work lately to use more of the VBIOS settings where
> possible. This patch adds support for using the VBIOS for TV connector
> detection and SSC information. On my T61 at least, using this patch keeps me
> from having to use the T61 TV ignore quirk.
> SSC (spread spectrum clock) is a EMI reducing feature 855+ chips support. It
> allows the OEM to provide an external reference clock and connect it to the
> GPU to modulate the display clock frequency. Since it requires an external
> part, information about its presence and frequency is supposed to be in the
> VBIOS general info block.
> I'm not sure how accurate the VBIOS info is for either TV or SSC info, so I'd
> like to get some feedback. Can people give this a try? It disables the TV
> quirk logic, so it'll rely on the VBIOS for getting TV output presence info.
> And it will unconditionally use SSC if it finds it, so you'll see a message
> (II) intel(0): using SSC reference clock of 100 MHz
> in your log if it ends up getting used.
> Please provide testing feedback on both features as a reply to this message.
> Intel-gfx mailing list
> Intel-gfx at lists.freedesktop.org
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