Commit c8a0bd42 authored Aug 21, 2014 by Paulo Zanoni Committed by Daniel Vetter Sep 03, 2014

drm/i915: send PCI_D3hot adapter opregion message on BDW RPM suspend



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@intel.com
Testcase: igt/pm_rpm/drm-resources-equal
Testcase: igt/pm_rpm/i2c
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

parent 47c2bd97

drivers/gpu/drm/i915/i915_drv.c

+22 −6

Original line number	Diff line number	Diff line
		@@ -1461,14 +1461,30 @@ static int intel_runtime_suspend(struct device *device)
		del_timer_sync(&dev_priv->gpu_error.hangcheck_timer);
		dev_priv->pm.suspended = true;

		/*
		* FIXME: We really should find a document that references the arguments
		* used below!
		*/
		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.
		* 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);
		}

		DRM_DEBUG_KMS("Device suspended\n");
		return 0;