[Intel-gfx] [PATCH 0/2] Automatic 6bpc dither for DisplayPort

Adam Jackson ajax at redhat.com
Mon Oct 10 22:33:33 CEST 2011

This fixes a rather irritating limitation of active dp->foo converters.
Many such (including all DP->VGA chips I can find on the market) come
equipped with only 2 DP lanes, which clips your dotclock to 144MHz at
8bpc.  Of the standard DMT modes, that means you lose 1600x1200 at 60 and
above.  Since these adaptors are marketed as supporting 1920x1200, we
might as well make that work, otherwise it's the driver that comes
out looking bad.

Granted you'll end up with 6bpc, which is hideous, but you're using
VGA so you don't get to complain about image quality.

Tested with a DP->VGA converter on an HP LP2480zx.

- ajax

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