Re: [Intel-gfx] [PATCH 3/7] drm/i915: Treat PCH eDP like DP in most places

Adam Jackson
2011-11-02T20:36:00Z

On 11/2/11 4:05 PM, Keith Packard wrote:
> On Wed, 02 Nov 2011 15:36:20 -0400, Adam Jackson<ajax@redhat.com> wrote:
>
>> The VBT is going to be crap.
>
> The only question then is what to do with hardware that doesn't have the
> DPCD value -- that's "new" in revision 0x11, after all.

It is? The DP 1.1a text for lane count is "For Rev.1.1, only the
following three values are supported. All other values are reserved." I
don't think that implies anything about what it meant in 1.0. It does
say that bits 7:5 of that register are reserved in 1.0 though; since it
doesn't have any versioning on bits 4:0 I'd think that means they're
interpreted the same in 1.0 as in 1.1.

Unless you have a copy of the 1.0 spec?

Again, not that it probably matters much. I think the installed base of
DP 1.0 sinks is zero, I've literally never seen one.

> How about this:
>
> commit 34ebe02cc78f20ae6b7865c5087c3b5ac7810185
> Author: Keith Packard<keithp@keithp.com>
> Date: Wed Nov 2 13:03:47 2011 -0700
>
> drm/i915: Use DPCD value for max DP lanes where possible
>
> Fall back to the VBT value for eDP monitors only when DPCD is missing
> the value.
>
> Signed-off-by: Keith Packard<keithp@keithp.com>

Reviewed-by: Adam Jackson <ajax@redhat.com>

- ajax