[Intel-gfx] [PATCH] drm/i915/gen9bc: Handle TGP PCH during suspend/resume

[Lyude Paul]

..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.

> --Imre
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> Intel-gfx at lists.freedesktop.org
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> 

-- 
Sincerely,
   Lyude Paul (she/her)
   Software Engineer at Red Hat
   
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