From: Ben Widawsky <benjamin.widawsky@intel.com>
Date: Wed, 5 Mar 2014 06:38:10 +0000 (-0800)
Subject: drm/i915: Fix PSR programming
X-Git-Tag: v3.13.8~43
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=bab00f228fc1d09d88e9d1feb74abe327a696b12;p=thirdparty%2Fkernel%2Fstable.git

drm/i915: Fix PSR programming

commit 24bd9bf54d45d28089251cdf62bf14323d1aa827 upstream.

| has a higher precedence than ?. Therefore, the calculation doesn't do
at all what you would expect. Thanks to Ken for convincing me that this
was indeed the issue. Send me back to C programmer school, please.

I'm sort of surprised PSR was continuing to work for people. It should
be broken IMO (and it was broken for me, but I had assumed it never
worked).

Regression from:
commit ed8546ac1f99b850879f07b1e9b06b42fb0a36d9
Author: Ben Widawsky <benjamin.widawsky@intel.com>
Date:   Mon Nov 4 22:45:05 2013 -0800

    drm/i915/bdw: Support eDP PSR

Cc: Rodrigo Vivi <rodrigo.vivi@gmail.com>
Cc: Kenneth Graunke <kenneth.w.graunke@intel.com>
Cc: Art Runyan <arthur.j.runyan@intel.com>
Reported-by: "Kumar, Kiran S" <kiran.s.kumar@intel.com>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 3e1b348de2446..6b50a14449a3d 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1634,7 +1634,7 @@ static void intel_edp_psr_enable_source(struct intel_dp *intel_dp)
 		val |= EDP_PSR_LINK_DISABLE;
 
 	I915_WRITE(EDP_PSR_CTL(dev), val |
-		   IS_BROADWELL(dev) ? 0 : link_entry_time |
+		   (IS_BROADWELL(dev) ? 0 : link_entry_time) |
 		   max_sleep_time << EDP_PSR_MAX_SLEEP_TIME_SHIFT |
 		   idle_frames << EDP_PSR_IDLE_FRAME_SHIFT |
 		   EDP_PSR_ENABLE);