On Tue, Nov 29, 2011 at 01:05:03PM +0000, Chris Wilson wrote: > On Tue, 29 Nov 2011 10:55:05 -0200, Eugeni Dodonov <eugeni.dodonov at intel.com> wrote: > > This allows to enable/disable rps and rc6 from userspace. This is > > necessary for to have predictable results from hardware counters, and also > > to provide a finer granularity over power control from userspace. > > Reading registers and counters is handled with i915_forcewake_user. So > the question is what benefit does htis give over module reload. It looks > far riskier... The observation architecture bspec says that we need to disable rc6, otherwise we'll get garbage in the gpu perf counters. But imo I think this should be handled in the kernel (we neeed to write tons of funny registers to set things up anyway), at least for the time-based perf counter sampling. For prototyping things with intel_reg_write disabling rc6 at module load time seems sufficient to me. -Daniel -- Daniel Vetter Mail: daniel at ffwll.ch Mobile: +41 (0)79 365 57 48
