[PATCH v1] drm/i915/selftest: Log throttle reasons on failure

[Rodrigo Vivi]

On Sat, Dec 07, 2024 at 08:14:42AM +0200, Raag Jadav wrote:
> Cc: Chris
> 
> On Fri, Dec 06, 2024 at 10:45:18AM -0500, Rodrigo Vivi wrote:
> > On Thu, Dec 05, 2024 at 01:44:13PM +0530, Raag Jadav wrote:
> > > Log throttle reasons on selftest failure which will be useful for
> > > debugging.
> > > 
> > > Signed-off-by: Raag Jadav <raag.jadav at intel.com>
> > > ---
> > >  drivers/gpu/drm/i915/gt/selftest_rps.c | 7 +++++--
> > >  1 file changed, 5 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/gt/selftest_rps.c b/drivers/gpu/drm/i915/gt/selftest_rps.c
> > > index dcef8d498919..1e0e59bc69b6 100644
> > > --- a/drivers/gpu/drm/i915/gt/selftest_rps.c
> > > +++ b/drivers/gpu/drm/i915/gt/selftest_rps.c
> > > @@ -478,8 +478,11 @@ int live_rps_control(void *arg)
> > >  			min, max, ktime_to_ns(min_dt), ktime_to_ns(max_dt));
> > >  
> > >  		if (limit == rps->min_freq) {
> > 
> > I was going to merge this, but then I noticed that this prints only
> > when the throttle moves that to our min_freq...  When PCODE throttle
> > the freq, the guaranteed freq can be at any point, not necessarily
> > to the minimal, so this print is not very effective in the end of the day
> 
> Makes me wonder why such a criteria at all?

very good question...
Perhaps we need to revamp entirely this selftest or kill it?

> 
> Raag
> 
> > > -			pr_err("%s: GPU throttled to minimum!\n",
> > > -			       engine->name);
> > > +			u32 throttle = intel_uncore_read(gt->uncore,
> > > +							 intel_gt_perf_limit_reasons_reg(gt));
> > > +
> > > +			pr_err("%s: GPU throttled to minimum frequency with reasons 0x%08x\n",
> > > +			       engine->name, throttle & GT0_PERF_LIMIT_REASONS_MASK);
> > >  			show_pstate_limits(rps);
> > >  			err = -ENODEV;
> > >  			break;
> > > -- 
> > > 2.34.1
> > >