[Intel-gfx] [PATCH 2/4] drm/i915: fix panel fitting filter coefficient select for Ironlake

[Zhenyu Wang]

Must set filter selection as hardcoded coefficients for medium 3x3
filtering, which matches vbios setting for Ironlake.

This fixes display corrupt issue on HP arrandale with new vbios.

Cc: Stable Team <stable at kernel.org>
Signed-off-by: Zhenyu Wang <zhenyuw at linux.intel.com>
---
 drivers/gpu/drm/i915/i915_reg.h      |    5 +++++
 drivers/gpu/drm/i915/intel_display.c |    2 +-
 2 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 5360bbd..d9319d7 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -2045,6 +2045,11 @@
 #define PFA_CTL_1               0x68080
 #define PFB_CTL_1               0x68880
 #define  PF_ENABLE              (1<<31)
+#define  PF_FILTER_MASK		(3<<23)
+#define  PF_FILTER_PROGRAMMED	(0<<23)
+#define  PF_FILTER_MED_3x3	(1<<23)
+#define  PF_FILTER_EDGE_ENHANCE	(2<<23)
+#define  PF_FILTER_EDGE_SOFTEN	(3<<23)
 #define PFA_WIN_SZ		0x68074
 #define PFB_WIN_SZ		0x68874
 #define PFA_WIN_POS		0x68070
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 5af3817..17fcb67 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1515,7 +1515,7 @@ static void igdng_crtc_dpms(struct drm_crtc *crtc, int mode)
 		/* Enable panel fitting for LVDS */
 		if (intel_pipe_has_type(crtc, INTEL_OUTPUT_LVDS)) {
 			temp = I915_READ(pf_ctl_reg);
-			I915_WRITE(pf_ctl_reg, temp | PF_ENABLE);
+			I915_WRITE(pf_ctl_reg, temp | PF_ENABLE | PF_FILTER_MED_3x3);
 
 			/* currently full aspect */
 			I915_WRITE(pf_win_pos, 0);
-- 
1.6.2.5