[PATCH 1/2] drm/i915: disable shared panel fitter for pipe

[Mika Kuoppala <mika.kuoppala@linux.intel.com>]

If encoder is switched off by BIOS, but the panel fitter is left on,
we never try to turn off the panel fitter and leave it still attached
to the pipe - which can cause blurry output elsewhere.

Based on work by Chris Wilson <chris@chris-wilson.co.uk>

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=58867
Cc: stable@vger.kernel.org
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
---
 drivers/gpu/drm/i915/intel_display.c |    9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index d75c6a0..9b5f0fb 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -3656,6 +3656,15 @@ static void i9xx_crtc_disable(struct drm_crtc *crtc)
 
 	intel_disable_plane(dev_priv, plane, pipe);
 	intel_disable_pipe(dev_priv, pipe);
+
+	if (!HAS_PCH_SPLIT(dev)) {
+		const u32 pctl = I915_READ(PFIT_CONTROL);
+
+		if ((pctl & PFIT_ENABLE) &&
+		    ((pctl & PFIT_PIPE_MASK) >> PFIT_PIPE_SHIFT) == pipe)
+			I915_WRITE(PFIT_CONTROL, 0);
+	}
+
 	intel_disable_pll(dev_priv, pipe);
 
 	intel_crtc->active = false;
-- 
1.7.9.5