[56/99] drm/i915: fix to setup display reference clock control on Ironlake

[Greg KH <gregkh@suse.de>]

[-- Attachment #1: drm-i915-fix-to-setup-display-reference-clock-control-on-ironlake.patch --]
[-- Type: text/plain, Size: 3024 bytes --]

2.6.31-stable review patch.  If anyone has any objections, please let us know.

------------------
From: Zhenyu Wang <zhenyuw@linux.intel.com>

commit c038e51e841581cc3fb9a76e5e16331331e9c85c upstream.

For new stepping of PCH, the display reference clock
is fully under driver's control. This one trys to setup
all needed reference clock for different outputs. Older
stepping of PCH chipset should be ignoring this.

This fixes output failure issue on newer PCH which requires
driver to take control of reference clock enabling.

Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 drivers/gpu/drm/i915/i915_reg.h      |    4 +--
 drivers/gpu/drm/i915/intel_display.c |   40 +++++++++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+), 2 deletions(-)

--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -1990,11 +1990,11 @@
 #define  DREF_CPU_SOURCE_OUTPUT_MASK		(3<<13)
 #define  DREF_SSC_SOURCE_DISABLE                (0<<11)
 #define  DREF_SSC_SOURCE_ENABLE                 (2<<11)
-#define  DREF_SSC_SOURCE_MASK			(2<<11)
+#define  DREF_SSC_SOURCE_MASK			(3<<11)
 #define  DREF_NONSPREAD_SOURCE_DISABLE          (0<<9)
 #define  DREF_NONSPREAD_CK505_ENABLE		(1<<9)
 #define  DREF_NONSPREAD_SOURCE_ENABLE           (2<<9)
-#define  DREF_NONSPREAD_SOURCE_MASK		(2<<9)
+#define  DREF_NONSPREAD_SOURCE_MASK		(3<<9)
 #define  DREF_SUPERSPREAD_SOURCE_DISABLE        (0<<7)
 #define  DREF_SUPERSPREAD_SOURCE_ENABLE         (2<<7)
 #define  DREF_SSC4_DOWNSPREAD                   (0<<6)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2442,6 +2442,46 @@ static int intel_crtc_mode_set(struct dr
 				  link_bw, &m_n);
 	}
 
+	/* Ironlake: try to setup display ref clock before DPLL
+	 * enabling. This is only under driver's control after
+	 * PCH B stepping, previous chipset stepping should be
+	 * ignoring this setting.
+	 */
+	if (IS_IGDNG(dev)) {
+		temp = I915_READ(PCH_DREF_CONTROL);
+		/* Always enable nonspread source */
+		temp &= ~DREF_NONSPREAD_SOURCE_MASK;
+		temp |= DREF_NONSPREAD_SOURCE_ENABLE;
+		I915_WRITE(PCH_DREF_CONTROL, temp);
+		POSTING_READ(PCH_DREF_CONTROL);
+
+		temp &= ~DREF_SSC_SOURCE_MASK;
+		temp |= DREF_SSC_SOURCE_ENABLE;
+		I915_WRITE(PCH_DREF_CONTROL, temp);
+		POSTING_READ(PCH_DREF_CONTROL);
+
+		udelay(200);
+
+		if (is_edp) {
+			if (dev_priv->lvds_use_ssc) {
+				temp |= DREF_SSC1_ENABLE;
+				I915_WRITE(PCH_DREF_CONTROL, temp);
+				POSTING_READ(PCH_DREF_CONTROL);
+
+				udelay(200);
+
+				temp &= ~DREF_CPU_SOURCE_OUTPUT_MASK;
+				temp |= DREF_CPU_SOURCE_OUTPUT_DOWNSPREAD;
+				I915_WRITE(PCH_DREF_CONTROL, temp);
+				POSTING_READ(PCH_DREF_CONTROL);
+			} else {
+				temp |= DREF_CPU_SOURCE_OUTPUT_NONSPREAD;
+				I915_WRITE(PCH_DREF_CONTROL, temp);
+				POSTING_READ(PCH_DREF_CONTROL);
+			}
+		}
+	}
+
 	if (IS_IGD(dev))
 		fp = (1 << clock.n) << 16 | clock.m1 << 8 | clock.m2;
 	else