On Thu, Aug 21, 2014 at 10:47:12PM +0100, Damien Lespiau wrote:
> On Thu, Aug 21, 2014 at 05:09:38PM -0300, Paulo Zanoni wrote:
> > From: Paulo Zanoni <paulo.r.zanoni@xxxxxxxxx>
> >
> > On BDW we're seeing a problem that after we runtime resume, the
> > outputs connected to DDI C are not detected: they don't appear in the
> > SDEISR register and GMBUS transactions don't work. They stop working
> > at the moment we call intel_opregion_notify_adapter() during runtime
> > suspend, but they don't go back to work when we call the same function
> > during runtime resume. They only work after we do a modeset and call
> > intel_opregion_notify_encoder(), but this point is already too late.
> >
> > While debugging, I tried to pass PCI_D3hot which is the value that
> > matches the spec, and it seems to have solved the problem. I couldn't
> > find any explanation of why this solves the problem, but there's also
> > no documented explanation - besides our code and git log - of why
> > Haswell should use PCI_D1, so keep this for now in order to keep BDW
> > runtime PM working.
> >
> > Also add a comment to point the fact that there's no spec documenting
> > all the weirdness involved here.
> >
> > Cc: kristen.c.accardi@xxxxxxxxx
> > Testcase: igt/pm_rpm/drm-resources-equal
> > Testcase: igt/pm_rpm/i2c
> > Signed-off-by: Paulo Zanoni <paulo.r.zanoni@xxxxxxxxx>
>
> There's still investigation to understand what the firmware is doing
> behind our backs, but the change looks likely to be correct and fixes
> the problem at hand so:
>
> Reviewed-by: Damien Lespiau <damien.lespiau@xxxxxxxxx>
>
> --
> Damien
>
> > ---
> > drivers/gpu/drm/i915/i915_drv.c | 28 ++++++++++++++++++++++------
> > 1 file changed, 22 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> > index 2dcc0d8..6f0c95f 100644
> > --- a/drivers/gpu/drm/i915/i915_drv.c
> > +++ b/drivers/gpu/drm/i915/i915_drv.c
> > @@ -1455,13 +1455,29 @@ static int intel_runtime_suspend(struct device *device)
> > dev_priv->pm.suspended = true;
> >
> > /*
> > - * current versions of firmware which depend on this opregion
> > - * notification have repurposed the D1 definition to mean
> > - * "runtime suspended" vs. what you would normally expect (D3)
> > - * to distinguish it from notifications that might be sent
> > - * via the suspend path.
> > + * FIXME: We really should find a document that references the arguments
> > + * used below!
> > */
> > - intel_opregion_notify_adapter(dev, PCI_D1);
> > + if (IS_HASWELL(dev)) {
> > + /*
> > + * current versions of firmware which depend on this opregion
> > + * notification have repurposed the D1 definition to mean
> > + * "runtime suspended" vs. what you would normally expect (D3)
> > + * to distinguish it from notifications that might be sent via
> > + * the suspend path.
> > + */
> > + intel_opregion_notify_adapter(dev, PCI_D1);
> > + } else {
> > + /*
> > + * On Broadwell, if we use PCI_D1 the PCH DDI ports will stop
> > + * being detected, and the call we do at intel_runtime_resume()
> > + * won't be able to restore them. Since PCI_D3hot matches the
> > + * actual specification and appears to be working, use it. Let's
> > + * assume the other non-Haswell platforms will stay the same as
> > + * Broadwell.
> > + */
> > + intel_opregion_notify_adapter(dev, PCI_D3hot);
I guess we could start to open betting pools whether this will grow until
we have all the pci states or not ;-)
Anyway, all 3 patches merged to dinq, thanks.
-Daniel
> > + }
> >
> > DRM_DEBUG_KMS("Device suspended\n");
> > return 0;
> > --
> > 2.0.1
> >
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--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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