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

[Raag Jadav]

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?

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
> >