[Intel-gfx] [PATCH 1/8] drm/i915/guc: Use _FW variants for mmio access in GuC irq handler

[Joonas Lahtinen]

Quoting Daniele Ceraolo Spurio (2018-03-23 19:17:49)
> 
> 
> On 23/03/18 05:34, Michał Winiarski wrote:
> > We're seeing "RPM wakelock ref not held during HW access" warning
> > otherwise. And since IRQ are synced for runtime suspend, we can use the
> > variant without wakeref assert.
> > 
> > Reported-by: Marta Löfstedt <marta.lofstedt at intel.com>
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105710
> > Signed-off-by: Michał Winiarski <michal.winiarski at intel.com>
> > Cc: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: Marta Löfstedt <marta.lofstedt at intel.com>
> > Cc: Michal Wajdeczko <michal.wajdeczko at intel.com>
> > ---
> >   drivers/gpu/drm/i915/intel_guc.c | 4 ++--
> >   1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_guc.c b/drivers/gpu/drm/i915/intel_guc.c
> > index 8f93f5bef8fd..6787a3116783 100644
> > --- a/drivers/gpu/drm/i915/intel_guc.c
> > +++ b/drivers/gpu/drm/i915/intel_guc.c
> > @@ -391,9 +391,9 @@ void intel_guc_to_host_event_handler(struct intel_guc *guc)
> >        * clears out the bit on handling the 1st interrupt.
> >        */
> >       spin_lock(&guc->irq_lock);
> > -     val = I915_READ(SOFT_SCRATCH(15));
> > +     val = I915_READ_FW(SOFT_SCRATCH(15));
> 
> GuC registers are in forcewake range, so don't we need to manually grab 
> forcewake if we use the _FW variant of the read/write macros?

Hmm, with the Bugzilla tag and all, wasn't this patch tested
specifically to fix the bug?

Regards, Joonas

PS. If there's a bugfix, it should really be a separate patch that can
be immediately merged and the bug should get fixed by the patch with
Bugzilla: is merged.

> 
> Daniele
> 
> >       msg = val & guc->msg_enabled_mask;
> > -     I915_WRITE(SOFT_SCRATCH(15), val & ~msg);
> > +     I915_WRITE_FW(SOFT_SCRATCH(15), val & ~msg);
> >       spin_unlock(&guc->irq_lock);
> >   
> >       if (msg & (INTEL_GUC_RECV_MSG_FLUSH_LOG_BUFFER |
> > 
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