[Intel-gfx] [PATCH] drm/i915: run intel_uncore_early_sanitize earlier on resume on non-VLV

[Paulo Zanoni]

From: Paulo Zanoni <paulo.r.zanoni at intel.com>

As far as I understand, intel_uncore_early_sanitize() was supposed to
be ran before any register access, but currently
intel_resume_prepare() is ran earlier, and it does register
access. I don't think it should be safe to be calling
I915_{READ,WRITE} without calling intel_uncore_early_sanitize() first.

One of the problems we currently have is that when we suspend/resume
BDW, the FPGA_DBG_RM_NOCLAIM bit becomes 1, so we end up printing an
"unclaimed register" message on resume, but this message doesn't
really seem to have been triggered by our driver or user space, since
the bit was not there before suspending, and gets there just after
resuming, before any of our own register accesses. So calling
intel_uncore_early_sanitize() as a first thing will allow us to stop
printing the error message, fixing the "bug".

v2: VLV is an exception to the early_sanitize() rule: it needs to do
stuff before calling early_sanitize(), so instead of calling it
earlier for every platform, we call it earlier for non-VLV by adding
the early_sanitize() call inside intel_resume_prepare(). This doesn't
look like the most-beautiful-solution-ever, but, well, at least it
fixes the bug. (Imre)

Cc: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Imre Deak <imre.deak at intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=83094
Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
---
 drivers/gpu/drm/i915/i915_drv.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index a05a1d0..f6d28f2 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -669,7 +669,6 @@ static int i915_drm_thaw_early(struct drm_device *dev)
 	if (ret)
 		DRM_ERROR("Resume prepare failed: %d,Continuing resume\n", ret);
 
-	intel_uncore_early_sanitize(dev, true);
 	intel_uncore_sanitize(dev);
 	intel_power_domains_init_hw(dev_priv);
 
@@ -1049,6 +1048,8 @@ static int snb_resume_prepare(struct drm_i915_private *dev_priv,
 
 	if (rpm_resume)
 		intel_init_pch_refclk(dev);
+	else
+		intel_uncore_early_sanitize(dev, true);
 
 	return 0;
 }
@@ -1056,6 +1057,9 @@ static int snb_resume_prepare(struct drm_i915_private *dev_priv,
 static int hsw_resume_prepare(struct drm_i915_private *dev_priv,
 				bool rpm_resume)
 {
+	if (!rpm_resume)
+		intel_uncore_early_sanitize(dev_priv->dev, true);
+
 	hsw_disable_pc8(dev_priv);
 
 	return 0;
@@ -1421,6 +1425,9 @@ static int vlv_resume_prepare(struct drm_i915_private *dev_priv,
 		i915_gem_restore_fences(dev);
 	}
 
+	if (!rpm_resume)
+		intel_uncore_early_sanitize(dev, true);
+
 	return ret;
 }
 
-- 
2.1.1