Re: [PATCH] drm/i915/pcode: Wait 10 seconds for pcode to settle

[Andi Shyti <andi.shyti@linux.intel.com>]

Hi Rodrigo,

On Wed, Jan 11, 2023 at 10:25:56AM -0500, Rodrigo Vivi wrote:
> On Wed, Jan 11, 2023 at 11:44:47AM +0100, Andi Shyti wrote:
> > From: Aravind Iddamsetty <aravind.iddamsetty@intel.com>
> > 
> > During module load not all the punit transaction have completed
> > and we might end up timing out, as shown by the following
> > warning:
> > 
> >    i915 0000:4d:00.0: drm_WARN_ON_ONCE(timeout_base_ms > 3)
> > 
> > Wait 10 seconds for the punit to settle and complete any
> > outstanding transactions upon module load.
> 
> 10 *SECONDS* ?!

Don't be alarmed :)

It's up to 10 seconds, otherwise we would end up waiting up to 3
minutes.

And I've seen a version (and you did as well) where those 3
minutes were raised to 6 (for the PVC particular case).

Thanks for checking this,
Andi

> > 
> > Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/7814
> > 
> > Signed-off-by: Aravind Iddamsetty <aravind.iddamsetty@intel.com>
> > Co-developed-by: Chris Wilson <chris@chris-wilson.co.uk>
> > Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> > Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_pcode.c | 35 ++++++++++++++++++++++++++----
> >  1 file changed, 31 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_pcode.c b/drivers/gpu/drm/i915/intel_pcode.c
> > index a234d9b4ed14..3db2ba439bb5 100644
> > --- a/drivers/gpu/drm/i915/intel_pcode.c
> > +++ b/drivers/gpu/drm/i915/intel_pcode.c
> > @@ -204,15 +204,42 @@ int skl_pcode_request(struct intel_uncore *uncore, u32 mbox, u32 request,
> >  #undef COND
> >  }
> >  
> > +static int pcode_init_wait(struct intel_uncore *uncore, int timeout_ms)
> > +{
> > +	if (__intel_wait_for_register_fw(uncore,
> > +					 GEN6_PCODE_MAILBOX,
> > +					 GEN6_PCODE_READY, 0,
> > +					 500, timeout_ms,
> > +					 NULL))
> > +		return -EPROBE_DEFER;
> > +
> > +	return skl_pcode_request(uncore,
> > +				 DG1_PCODE_STATUS,
> > +				 DG1_UNCORE_GET_INIT_STATUS,
> > +				 DG1_UNCORE_INIT_STATUS_COMPLETE,
> > +				 DG1_UNCORE_INIT_STATUS_COMPLETE, timeout_ms);
> > +}
> > +
> >  int intel_pcode_init(struct intel_uncore *uncore)
> >  {
> > +	int err;
> > +
> >  	if (!IS_DGFX(uncore->i915))
> >  		return 0;
> >  
> > -	return skl_pcode_request(uncore, DG1_PCODE_STATUS,
> > -				 DG1_UNCORE_GET_INIT_STATUS,
> > -				 DG1_UNCORE_INIT_STATUS_COMPLETE,
> > -				 DG1_UNCORE_INIT_STATUS_COMPLETE, 180000);
> > +	/*
> > +	 * Wait 10 seconds so that the punit to settle and complete
> > +	 * any outstanding transactions upon module load
> > +	 */
> > +	err = pcode_init_wait(uncore, 10000);
> > +
> > +	if (err) {
> > +		drm_notice(&uncore->i915->drm,
> > +			   "Waiting for HW initialisation...\n");
> > +		err = pcode_init_wait(uncore, 180000);
> > +	}
> > +
> > +	return err;
> >  }
> >  
> >  int snb_pcode_read_p(struct intel_uncore *uncore, u32 mbcmd, u32 p1, u32 p2, u32 *val)
> > -- 
> > 2.34.1
> >