From 55ec45c2ced1a4b1e7cd2e7e306101f328958760 Mon Sep 17 00:00:00 2001
From: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Date: Tue, 15 Dec 2015 16:25:08 +0200
Subject: [PATCH] drm/i915: Detect and clear unclaimed access on resume
If something, the usual suspect being bios, access hw
behind our back, don't let it slide into situation where
normal register access will detect this and spit out
a warn on into dmesg. On some bdw bioses this happens
during igt/bat run always and as there is not much we can
do about it, its better just to detect and flush this
explicitly on resume and only print a debug message.
v2: use DRM_DEBUG_DRIVER (Chris)
v3: s/access/mmio, s/prior/prior to, s/dev/dev_priv
Testcase: igt/pm_rpm/basic-rte
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Paulo Zanoni <przanoni@gmail.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
[Mika: fixed merge conflict]
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1450189512-30360-3-git-send-email-mika.kuoppala@intel.com
---
drivers/gpu/drm/i915/i915_drv.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 3ac616d7363ba..288fec7691dc3 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -1501,6 +1501,10 @@ static int intel_runtime_suspend(struct device *device)
enable_rpm_wakeref_asserts(dev_priv);
WARN_ON_ONCE(atomic_read(&dev_priv->pm.wakeref_count));
+
+ if (intel_uncore_unclaimed_mmio(dev_priv))
+ DRM_ERROR("Unclaimed access detected prior to suspending\n");
+
dev_priv->pm.suspended = true;
/*
@@ -1549,6 +1553,8 @@ static int intel_runtime_resume(struct device *device)
intel_opregion_notify_adapter(dev, PCI_D0);
dev_priv->pm.suspended = false;
+ if (intel_uncore_unclaimed_mmio(dev_priv))
+ DRM_DEBUG_DRIVER("Unclaimed access during suspend, bios?\n");
intel_guc_resume(dev);
--
2.30.2