[PATCH] drm/i915: Force full PSR setup during crtc enable.

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

Some registers set during setup might not be persistent after suspend/resume,
and also on crtc off/on cycles.

This was causing bugs for some people that was unable to get PSR entry state
after suspend/resume cycle.

v2: Adding some comments and better commit message explaining why this is
needed. (by Paulo)
v3: Moving psr.setup_done reset to crtc_enable because same issues might apply
also on crtc off/on cycle. (by Daniel)

Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Joe Konno <joe.konno@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
---
 drivers/gpu/drm/i915/intel_display.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index b5cbb28..077ab0e 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -3938,6 +3938,10 @@ static void intel_crtc_enable_planes(struct drm_crtc *crtc)
 
 	mutex_lock(&dev->struct_mutex);
 	intel_update_fbc(dev);
+	/* Forcing a full init sequence here to make sure all
+	* registers are properly set. Some might not be persistent after
+	* crtc on/off cycle. */
+	dev_priv->psr.setup_done = false;
 	intel_edp_psr_update(dev);
 	mutex_unlock(&dev->struct_mutex);
 }
-- 
1.9.3