Messages in this thread | | | Date | Wed, 02 Nov 2011 15:36:20 -0400 | From | Adam Jackson <> | Subject | Re: [Intel-gfx] [PATCH 3/7] drm/i915: Treat PCH eDP like DP in most places |
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On 11/2/11 1:31 PM, Keith Packard wrote: > On Wed, 02 Nov 2011 13:13:52 -0400, Adam Jackson<ajax@redhat.com> wrote: > >> Given the choice of trusting DPCD or the VBT, I'd definitely prefer >> DPCD. > > Except that the DPCD is coded into the monitor while the VBT is done by > the platform. And, it's the platform which may neglect to connect some > of the wires.
My reasoning about this has been:
The maximum link configuration in DPCD is going to fit - and minimally fit - the maximum supported configuration (depth/rate/size/etc), because otherwise the hardware would have been more expensive to produce.
The VBT is going to be crap.
But as always, "do what the Windows driver does" seems like a good strategy. Do we know?
> Any bets on how long until we find a machine that has right value in the > VBT and the wrong one in DPCD? Or a machine with wrong values in both places?
I will happily pay $20 to the first person to find a monitor with broken link/lane in DPCD, on the understanding that they take it (the $20) to the nearest hardware store, buy a hammer, and smash the monitor. Preferably with the video uploaded to youtube.
- ajax
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