Re: i915 SSC Patch

From: Keith Packard
Date: Fri Jul 29 2011 - 14:45:35 EST


On Fri, 29 Jul 2011 13:55:35 +0100, Ben Brewer <ben.brewer@xxxxxxxxxxxxxxx> wrote:

> I've added a global SSC (Spread Spectrum Clock) parameter to the i915
> driver, since having SSC enabled breaks (distorts) VGA output on some
> Core i5/i7 chips (see https://bugs.freedesktop.org/show_bug.cgi?id=38750).
> SSC is still enabled by default so the behaviour won't change but
> setting the global_use_ssc parameter will turn this feature off and
> allow affected devices to function correctly (notably the Dell Vostro
> 3300).

The question I have is why is SSC enabled on the VGA output at all? I
don't see any way VGA could ever tolerate it.

--
keith.packard@xxxxxxxxx

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