[Intel-gfx] [PATCH v2] drm/i915: Per-DDI I_boost override

[Damien Lespiau]

On Fri, Jul 03, 2015 at 06:21:58PM +0300, Ville Syrjälä wrote:
> > In the old VBT spec I have, each child_dev_config is supposed to have
> > only 33 bytes. But in this patch you're increasing it to 38. I believe
> > this is what's causing the errors I see when I boot my BDW.
> > 
> > Are you sure they increased the VBT's ChildDevInfo to more than 33
> > bytes? I don't have access to your VBT spec right now, so I can't do a
> > proper review or a suggestion on how to fix the problem.
> 
> The size depends on the version. On BSW last I looked it was maybe 36 or
> 37 bytes.
> 
> I'm not sure we want to change common_child_dev_config since it's meant
> to be some kind of common stuff. So maybe add another member into the
> union for this stuff. Of course that still incrases the size of the union
> so other changes are required to make it work.
> 
> Fortunately we copy these things out from the VBT, so I think just
> making sure the memcpy() doesn't try to copy too much and fixing the size
> check should be all that's needed. That would leave any extra we didn't
> fill with the copy zeroed, and if having it zeroed isn't good enough
> we can of course sprinkle more version checks around.
> 
> And I guess we should still check that the size is at least 33 bytes
> since that was the official size for the longest time.

So child_dev_size lies to us?

-- 
Damien