[Intel-gfx] [PATCH 1/2] drm/i915/cnp: Don't touch other PCH clock gating bits.

[Rodrigo Vivi]

Don't touch other bits. My bad.

I haven't seen any case where those other bits appeard to be
set before we touch it, but it is safe to avoid touching
other bits we weren't told to touch.

Fixes: 0a46ddd57c9e ("drm/i915/cnp: Wa 1181: Fix Backlight issue")
Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
---
 drivers/gpu/drm/i915/intel_pm.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index fa9055a4f790..09ecc8e3b2d3 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -8370,7 +8370,8 @@ static void cnp_init_clock_gating(struct drm_i915_private *dev_priv)
 		return;
 
 	/* Wa #1181 */
-	I915_WRITE(SOUTH_DSPCLK_GATE_D, CNP_PWM_CGE_GATING_DISABLE);
+	I915_WRITE(SOUTH_DSPCLK_GATE_D, I915_READ(SOUTH_DSPCLK_GATE_D) |
+		   CNP_PWM_CGE_GATING_DISABLE);
 }
 
 static void cnl_init_clock_gating(struct drm_i915_private *dev_priv)
-- 
2.13.2