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[SKL-DMC-BUGFIX,3/5] drm/i915/skl: Do not disable cdclk PLL if csr firmware is present

Message ID 1438860217-5544-1-git-send-email-animesh.manna@intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Animesh Manna Aug. 6, 2015, 11:23 a.m. UTC 
While display engine entering into low power state no need to disable
cdclk pll as CSR firmware of dmc will take care. If pll is already
enabled firmware execution sequence will be blocked. This is one
of the criteria for dmc to work properly.

v1: Initial version.

v2: Based on review comment from Daniel added code commnent.

Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Damien Lespiau <damien.lespiau@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Sunil Kamath <sunil.kamath@intel.com>
Signed-off-by: Animesh Manna <animesh.manna@intel.com>
Signed-off-bt: Vathsala Nagaraju <vathsala.nagaraju@intel.com>
Signed-off-by: Rajneesh Bhardwaj <rajneesh.bhardwaj@intel.com>
---
 drivers/gpu/drm/i915/intel_display.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)
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Patch

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index af0bcfe..1f8d704 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -5675,10 +5675,16 @@  void skl_uninit_cdclk(struct drm_i915_private *dev_priv)
 	if (I915_READ(DBUF_CTL) & DBUF_POWER_STATE)
 		DRM_ERROR("DBuf power disable timeout\n");
 
-	/* disable DPLL0 */
-	I915_WRITE(LCPLL1_CTL, I915_READ(LCPLL1_CTL) & ~LCPLL_PLL_ENABLE);
-	if (wait_for(!(I915_READ(LCPLL1_CTL) & LCPLL_PLL_LOCK), 1))
-		DRM_ERROR("Couldn't disable DPLL0\n");
+	/* 
+	 * DMC assumes ownership of LCPLL and will get confused if we touch it. 
+	 */
+	if (dev_priv->csr.dmc_payload) {
+		/* disable DPLL0 */
+		I915_WRITE(LCPLL1_CTL, I915_READ(LCPLL1_CTL) &
+					~LCPLL_PLL_ENABLE);
+		if (wait_for(!(I915_READ(LCPLL1_CTL) & LCPLL_PLL_LOCK), 1))
+			DRM_ERROR("Couldn't disable DPLL0\n");
+	}
 
 	intel_display_power_put(dev_priv, POWER_DOMAIN_PLLS);
 }