Hi Janusz, On Wed, Oct 22, 2025 at 12:22:41PM +0200, Janusz Krzysztofik wrote: > On Friday, 17 October 2025 10:45:23 CEST Andi Shyti wrote: > > Hi Janusz, > > > > > diff --git a/drivers/gpu/drm/i915/gt/selftest_migrate.c b/drivers/gpu/drm/ > i915/gt/selftest_migrate.c > > > index 54bc447efce0b..cde755751a0ba 100644 > > > --- a/drivers/gpu/drm/i915/gt/selftest_migrate.c > > > +++ b/drivers/gpu/drm/i915/gt/selftest_migrate.c > > > @@ -710,7 +710,8 @@ static int threaded_migrate(struct intel_migrate > *migrate, > > > thread[i].tsk = tsk; > > > } > > > > > > - msleep(10 * n_cpus); /* start all threads before we kthread_stop() > */ > > > + /* start all threads before we kthread_stop() */ > > > + msleep((intel_vm_no_concurrent_access_wa(migrate->context->vm->i915) > ? 100 : 10) * n_cpus); > > > > First question, why 100? Second question why not 100 for > > everyone? > > 100ms because 10ms occurred too short on CHV / BXT+VTD with GGTT workarounds, > and I've empirically determined a sufficient delay of 100ms, as mentioned in > commit description. Do you want me to add that information to the inline > comment as well? > > Not for everyone because 10ms has proven to be sufficient for platforms with > no CHV / BXT+VTD specific workarounds. Do you want me to use a single value?
Yes, makes sense, please add a comment explaining that the values have been found empirically. Thanks, Andi
