Re: [PATCH] drm/i915: Add has_psr-flag to gen9lp

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Thu, Sep 28, 2017 at 10:51:42AM +0000, David Weinehall wrote:
> On Thu, Sep 28, 2017 at 04:20:29AM +0000, Rodrigo Vivi wrote:
> > On Wed, Sep 27, 2017 at 5:14 AM David Weinehall <
> > david.weinehall@linux.intel.com> wrote:
> > 
> > > On Tue, Aug 08, 2017 at 12:50:51PM -0700, Rodrigo Vivi wrote:
> > > > a long time ago I had agreed with Daniel that we would only add new
> > > > platforms after it was enabled by default on previous platforms.
> > > > a big reason for that is that we was willing to reduce the platforms
> > > > to validate and do better validation one by one before enabling.
> > > >
> > > > However now I believe it would be beneficial to have that supported
> > > > added so we can get more brave people using in different platforms so
> > > > we could capture more corner cases before we enable it by default.
> > > > Also we can still enable by default one platform at time if needed.
> > > >
> > > > So:
> > > >
> > > > Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
> > > >
> > > > I also checked the spec to see if there was anything else new or
> > > > different for these platforms and didn't find anything so:
> > > >
> > > > Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
> > > >
> > > > But let's wait a bit to merge to give Daniel or others a time to nack ;)
> > >
> > > An update: while testing revealed that our BXT-P RVP doesn't work with
> > > PSR, the GLK definitely does. CI would like to do PSR testing on GLK,
> > > which obviously isn't possible if PSR is reported as unsupported on GLK.
> > >
> > > Based on BSpec alone the PSR failure on BXT-P shouldn't be a
> > > Broxton/Apollo Lake issue, but rather an issue with the RVP board
> > > (or the panel), so I'd say that this patch still makes sense.
> > 
> > 
> > It would be very important if we could narrow down the issue on BXT.
> > Panel?! Bios?! Missing Workaround? Different user space?
> 
> Agreed. I haven't been able to find any newer BIOS for that device,
> the user space should be the same.
> 
> Missing workaround might well be the case, and the panel is definitely
> not the same as the one the GLK has. We have several other panels that
> could be tested with though.
> 
> > One of the biggest problem with PSR is that when it works well in all
> > machines we have and we enable it we end up finding someone in the
> > community with a machine that does not work well.
> 
> "Luckily" I own one of those machines :P
> 
> > We have an opportunity to investigate and understand very well what
> > are the issues on this BXT. We shouldn't loose track of it.
> 
> That opportunity is now rapidly fleeing, since the HW in
> question is a BXT B0, for which the "drop workarounds" patch series
> has already been submitted and gotten a R-B.

Agree. But since it was a while ago I was trying to hit CI retest on that,
but I couldn't. So could you please resubmit? I just want to see if that
will cause some noise that will force us to file a bug so CI doesn't start
flip-floping again because of this.

> 
> > And maybe adding that to CI we will be forced to record the bug! ;)
> > 
> > >
> > > After all it only changes gen9lp to report that they *can* support PSR
> > > (thus allowing for testing of PSR on such platforms), it doesn't enable
> > > it by default.
> > >
> > > So I'd like to nudge once more that this patch be merged.
> > 
> > I agree. Let's add it. Also good to enable on CNL as well. If the panel
> > that you have there on CNL that is on CI doesn't support it you are about
> > to recurve some panels that does support PSR2.
> 
> Yeah, enabling on CNL too makes sense and getting systematic PSR2 testing
> would be awesome.

nevermind... on another review I notice cnl is already there imported from HSW_FEATURES.

> 
> "recurve" => "receive"?

yeap...
(phone auto-corrector believe recurve is the best option for recieve than receive :))

Thanks,
Rodrigo.

> 
> 
> Kind regards, David
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