[PATCH] drm/i915: Fix PSR programming

Ben Widawsky
2014-03-05T06:38:39Z

| 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

I am pretty certain PSR is disabled by default, so no CC stable.

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>
---
drivers/gpu/drm/i915/intel_dp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index c512d78..2c0ceb4 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1723,7 +1723,7 @@ 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);
--
1.9.0