[PATCH 0/5] drm/etnaviv: Ignore MC bit when checking for runtime suspend

[Chris Healy]

Would this power difference with the GPU also apply with the GC3000 in the
i.MX6qp or the GC2000 in the i.MX6q?

On Thu, Jun 25, 2020 at 8:04 AM Guido Günther <agx at sigxcpu.org> wrote:

> Hi,
> On Tue, Mar 03, 2020 at 12:55:04PM +0100, Lucas Stach wrote:
> > On Mo, 2020-03-02 at 20:13 +0100, Guido Günther wrote:
> > > At least GC7000 fails to enter runtime suspend for long periods of
> time since
> > > the MC becomes busy again even when the FE is idle. The rest of the
> series
> > > makes detecting similar issues easier to debug in the future by
> checking
> > > all known bits in debugfs and also warning in the EBUSY case.
> >
> > Thanks, series applied to etnaviv/next.
> >
> > > Tested on GC7000 with a reduced runtime delay of 50ms. Patches are
> > > against next-20200226.
> >
> > I've already wondered if 200ms is too long, 50ms sounds more
> > reasonable. Do you have any numbers on the power draw on the i.MX8M
> > with idle GPU, vs. being fully power gated?
>
> The difference is at least 250mW. It makes a huge difference over here.
> We hit
>
> https://lore.kernel.org/dri-devel/20200614064601.7872-1-navid.emamdoost@gmail.com/
> recently and you notice instantly when that happens when looking at the
> SoC temperature.
>
> Cheers,
>  -- Guido
> >
> > Regards,
> > Lucas
> >
> > > Thanks to Lucas Stach for pointing me in the right direction.
> > >
> > > Guido Günther (5):
> > >   drm/etnaviv: Fix typo in comment
> > >   drm/etnaviv: Update idle bits
> > >   drm/etnaviv: Consider all kwnown idle bits in debugfs
> > >   drm/etnaviv: Ignore MC when checking runtime suspend idleness
> > >   drm/etnaviv: Warn when GPU doesn't idle fast enough
> > >
> > >  drivers/gpu/drm/etnaviv/etnaviv_gpu.c  | 26 ++++++++++++++++++++++----
> > >  drivers/gpu/drm/etnaviv/state_hi.xml.h |  7 +++++++
> > >  2 files changed, 29 insertions(+), 4 deletions(-)
> > >
> >
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