[PATCH v3 0/2] drm/i915/display: Power request asserting/deasserting

[Kahola, Mika]

> -----Original Message-----
> From: Jadav, Raag <raag.jadav at intel.com>
> Sent: Thursday, 31 October 2024 14.59
> To: Kahola, Mika <mika.kahola at intel.com>
> Cc: intel-gfx at lists.freedesktop.org; Sousa, Gustavo <gustavo.sousa at intel.com>;
> jani.nikula at linux.intel.com
> Subject: Re: [PATCH v3 0/2] drm/i915/display: Power request
> asserting/deasserting
> 
> On Thu, Oct 31, 2024 at 01:40:25PM +0200, Mika Kahola wrote:
> > There is a HW issue that arises when there are race conditions between
> > TCSS entering/exiting TC7 or TC10 states while the driver is
> > asserting/deasserting TCSS power request. As a workaround, Display
> > driver will implement a mailbox sequence to ensure that the TCSS is in
> > TC0 when TCSS power request is asserted/deasserted.
> >
> > The sequence is the following
> >
> > 1. Read mailbox command status and wait until run/busy bit is
> >    clear
> > 2. Write mailbox data value '1' for power request asserting
> >    and '0' for power request deasserting 3. Write mailbox command
> > run/busy bit and command value with 0x1 4. Read mailbox command and
> > wait until run/busy bit is clear
> >    before continuing power request.
> >
> > while at it, let's start using struct intel_display instead of struct
> > drm_i915_private as well.
> 
> Perhaps this needs to be its own patch since it's unrelated to the series.

There was a request from Jani to start using intel_display instead of drm_i915_private also with the calling function. So this is perhaps remotely related to this WA I included this here. 

> 
> Raag