On Sun, 2019-03-03 at 22:51 +0100, Rafael J. Wysocki wrote: > On Sun, Mar 3, 2019 at 10:20 PM Srinivas Pandruvada > <srinivas.pandruv...@linux.intel.com> wrote: > > > > On Sun, 2019-03-03 at 18:03 +0100, Rafael J. Wysocki wrote: > > > On Fri, Mar 1, 2019 at 6:39 PM Srinivas Pandruvada > > > <srinivas.pandruv...@linux.intel.com> wrote: > > > > > > > > On Fri, 2019-03-01 at 13:43 +0100, Rafael J. Wysocki wrote: > > > > > Hi All, > > > > > > > > > > This is how I would fix the issue reported in BZ 200759 (see > > > > > thisdev > > > > > patch series > > > > > from Yu too: > > > > > https://marc.info/?l=linux-pm&m=155137672924029&w=2) > > > > > . > > > > > > > > > > Patch [1/2] causes intel_pstate to update all policies if it > > > > > gets > > > > > a > > > > > _PPC change > > > > > notification and sees a global turbo disable/enable change. > > > > > > > > > > Patch [2/2] makes it update cpuinfo.max_freq for all policies > > > > > in > > > > > those cases. > > > > > > > > > > The patches here have not been tested yet, so testing would > > > > > be > > > > > much > > > > > appreciated. > > > > > > > > > > Of course, comments are welcome too! > > > > > > > > This is the only platform, someone reported such issue. > > > > > > I don't think this matters. > > > > > > First, it doesn't mean that no other problems have this problem. > > > > > > Second, the current handling of > > > MSR_IA32_MISC_ENABLE_TURBO_DISABLE > > > changes in intel_pstate is not sufficient if the changes is from > > > set > > > to unset anyway. > > > > Any platform with HWP, you can't even notify of this change. So any > > platform beyond SKL is not useful. > > Do you mean that HWP platforms don't supply _PPS (as a rule) and so > they don't send _PPC notifications? Is there anything they do > instead > of it? There are other methods like PL1 budget limit for such cases. FW can just change the config TDP level.
> > That's fair enough, but the point is that the driver doesn'dev_t do > the > right thing even if the platform does send a _PPC notification. _PPC notification is to indicate levels in _PSS not to disable/enable turbo via IA32_MISC_*. The platform could have just set _PPC to 1 or to TAR-1. Here _PPC is sent for somthing more than just changing _PSS max level. Do we have bug in if _PPC just changes performance level? > > > Fixing is always good :-) > > Well, I can only agree with that ...