[igt-dev] [PATCH i-g-t 2/6] i915/i915_pm_rpm.c: create PC state subtest group

[Anshuman Gupta]

On 2020-12-09 at 16:47:01 +0000, Chris Wilson wrote:
> Quoting Anshuman Gupta (2020-12-09 16:25:02)
> > On 2020-12-09 at 16:25:55 +0000, Chris Wilson wrote:
> > > Quoting Anshuman Gupta (2020-12-09 16:06:38)
> > > > Create a separate igt test group and move package C
> > > > state in to this subgroup.
> > > > Run powertop --auto-tune to tune SOC power configuration
> > > > for package C state tests.
> > > > 
> > > > Signed-off-by: Anshuman Gupta <anshuman.gupta at intel.com>
> > > > ---
> > > >  tests/i915/i915_pm_rpm.c | 35 +++++++++++++++++++++++++++++++----
> > > >  1 file changed, 31 insertions(+), 4 deletions(-)
> > > > 
> > > > diff --git a/tests/i915/i915_pm_rpm.c b/tests/i915/i915_pm_rpm.c
> > > > index af55b569..42bc44d9 100644
> > > > --- a/tests/i915/i915_pm_rpm.c
> > > > +++ b/tests/i915/i915_pm_rpm.c
> > > > @@ -832,6 +832,25 @@ static void basic_subtest(void)
> > > >         /* XXX Also we can test wake up via exec nop */
> > > >  }
> > > >  
> > > > +static bool setup_powertop(void)
> > > > +{
> > > > +       FILE *fp;
> > > > +       char tmp[512];
> > > > +
> > > > +       fp = popen("powertop --auto-tune", "r");
> > > 
> > > Doesn't this defeat the point of having it work out of the box?
May be misunderstood your comment, is it PC state or powertop should work
out of box ?
> > > -Chris
> > Yes, but there is no other way as PC state are being dependent on other
> > non-gfx devices as well. These test kept disabled since gen9 platforms.
> 
> Could you be explicit in the steps required so that it is clear that
> powertop is not working around our own bugs?
We need to run powertop --auto-tune to tune SOC power configuration in order
to attain deeper package C state.
Without running "powertop --auto-tune" we may not hit to PC8/PC10 state
(other non-gfx devices can also block the PC8/PC10 state).
We don't want to fail these test due to other non-gfx devices, so it is
better to tune SOC power configuration by power-top.

Thanks,
Anshuman Gupta.
  
> -Chris