> -----Original Message-----
> From: Lyude Paul <ly...@redhat.com>
> Sent: Wednesday, February 10, 2021 1:34 AM
> To: Deak, Imre <imre.d...@intel.com>; Surendrakumar Upadhyay, TejaskumarX
> <tejaskumarx.surendrakumar.upadh...@intel.com>; Gupta, Anshuman
> <anshuman.gu...@intel.com>
> Cc: intel-gfx@lists.freedesktop.org; Pandey, Hariom
> <hariom.pan...@intel.com>
> Subject: Re: [Intel-gfx] [PATCH] drm/i915/gen9bc: Handle TGP PCH during
> suspend/resume
>
> ..snip.. (comments down below)
>
> On Tue, 2021-02-02 at 18:14 +0200, Imre Deak wrote:
> >
> > BSpec says about this WA for both ICL and TGL:
> > """
> > Display driver should set and clear register offset 0xC2000 bit #7 as
> > last step in programming south display registers in preparation for
> > entering S0ix state, or set 0xC2000 bit #7 on S0ix entry and clear it
> > on S0ix exit.
> >
> > """
> >
> > This means to me the WA is only relevant for S0ix and we can implement
> > it by setting/clearing 0xC2000 bit #7 right before entering/right
> > after exiting S0ix. This is done atm on PCH_ICP..PCH_MCC in
> > intel_display_power_suspend_late()/intel_display_power_resume_early(),
> > so I'd move the WA for all platforms there.
> >
> > I assume the current code in irq_reset() was the first alternative to
> > implement the WA, but it wasn't enough. Not sure why, maybe there is a
> > south display register access after irq_reset() during suspend. Adding
> > Anshuman for an idea on that.
> >
>
> Poking Anshuman here, is there any update on this? I'm looking to push these
> patches forward as some of Red Hat's hardware partners are very eager for this
> to get upstream asap as we're running out of time from our end. If you can
> answer this, I can handle respinning this patch as needed.
My sincere apology, I had missed this thread.
We have decided to keep the alternative WA i.e setting/clearing 0xC2000 bit #7
before entering after exiting s0ix to fix the deeper s0ix power consumption
issues on ICL_PCH
families platforms. This alternative WA was added to B.Spec on our request.
But on TGL_PCH first alternative WA logic i.e in irq_reset() was working to
attain deeper s0ix residencies so
we haven't changed that.
Thanks,
Anshuman Gupta
>
> > --Imre
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> >
>
> --
> Sincerely,
> Lyude Paul (she/her)
> Software Engineer at Red Hat
>
> Note: I deal with a lot of emails and have a lot of bugs on my plate. If
> you've
> asked me a question, are waiting for a review/merge on a patch, etc. and I
> haven't responded in a while, please feel free to send me another email to
> check
> on my status. I don't bite!
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