> -----Original Message----- > From: Jadav, Raag <raag.jadav@xxxxxxxxx> > Sent: Thursday, 31 October 2024 14.59 > To: Kahola, Mika <mika.kahola@xxxxxxxxx> > Cc: intel-gfx@xxxxxxxxxxxxxxxxxxxxx; Sousa, Gustavo <gustavo.sousa@xxxxxxxxx>; > jani.nikula@xxxxxxxxxxxxxxx > 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
