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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>
This commit is contained in:
Paulo Zanoni 2014-08-21 17:09:38 -03:00 committed by Daniel Vetter
parent 47c2bd97cf
commit c8a0bd42df
1 changed files with 22 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
drivers/gpu/drm/i915/i915_drv.c
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@ -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;