The patch below does not apply to the 3.11-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

>From 0cc4b69960f3d1231023ad5de6cacbc1fbee2a88 Mon Sep 17 00:00:00 2001
From: Rodrigo Vivi <[email protected]>
Date: Thu, 3 Oct 2013 13:31:26 -0300
Subject: [PATCH] drm/i915: Mask LPSP to get PSR working even with Power Well
 in use by audio.

Power Well in use forces constantly PSR to exit.
On recent Kernel I noticed that PSR Performance Counter was always 0
indicating that PSR was never really achieved.
By masking LPSP, PSR can work normally and save power on Haswell.

Two bugs had been raised with PSR flag enabled:
- "Screen flickers when booted by enabling PSR in the kernel 
(i915.enable_psr=1) , the system is booting to a gray screen."
- "When booting the DUT with PSR feature enabled in the kernel 
(i915.enable_psr=1) , the system is booting to a gray screen."

Both bugs has been fixed by this patch.

v2: proper comment for -fixes

Tested-by: Selvaraj, Elavarasan <[email protected]>
Signed-off-by: Rodrigo Vivi <[email protected]>
Cc: [email protected]
Signed-off-by: Daniel Vetter <[email protected]>

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 79c14e29..2c555f91 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1467,7 +1467,7 @@ static void intel_edp_psr_setup(struct intel_dp *intel_dp)
 
        /* Avoid continuous PSR exit by masking memup and hpd */
        I915_WRITE(EDP_PSR_DEBUG_CTL, EDP_PSR_DEBUG_MASK_MEMUP |
-                  EDP_PSR_DEBUG_MASK_HPD);
+                  EDP_PSR_DEBUG_MASK_HPD | EDP_PSR_DEBUG_MASK_LPSP);
 
        intel_dp->psr_setup_done = true;
 }

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