diff options
| author | Chris Wilson <chris@chris-wilson.co.uk> | 2010-12-03 21:35:48 +0000 |
|---|---|---|
| committer | Chris Wilson <chris@chris-wilson.co.uk> | 2010-12-05 00:37:36 +0000 |
| commit | c1858123dba4a9e40355363ac7a153ea23a5315d (patch) | |
| tree | 0f5c60c6fdf413b78dbe7d8c1f3927db925908de /drivers/gpu/drm | |
| parent | a589b9f429ac0e5bcdebda0f74ee313d39d69b7f (diff) | |
drm/i915: Enable CB tuning of the Display PLL
Magic numbers from the specs. This is supposed to allow the PLL some
variance to improve jitter performance and VCO headroom across
manufacturing and environmental variations.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Diffstat (limited to 'drivers/gpu/drm')
| -rw-r--r-- | drivers/gpu/drm/i915/i915_reg.h | 1 | ||||
| -rw-r--r-- | drivers/gpu/drm/i915/intel_display.c | 17 |
2 files changed, 17 insertions, 1 deletions
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index 998457063d5..06175e98c5b 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -2712,6 +2712,7 @@ #define PCH_DPLL(pipe) _PIPE(pipe, PCH_DPLL_A, PCH_DPLL_B) #define PCH_FPA0 0xc6040 +#define FP_CB_TUNE (0x3<<22) #define PCH_FPA1 0xc6044 #define PCH_FPB0 0xc6048 #define PCH_FPB1 0xc604c diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index e3b8d0dc7a7..f2aa76bd72c 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -3857,6 +3857,22 @@ static int intel_crtc_mode_set(struct drm_crtc *crtc, reduced_clock.m2; } + /* Enable autotuning of the PLL clock (if permissible) */ + if (HAS_PCH_SPLIT(dev)) { + int factor = 21; + + if (is_lvds) { + if ((dev_priv->lvds_use_ssc && + dev_priv->lvds_ssc_freq == 100) || + (I915_READ(PCH_LVDS) & LVDS_CLKB_POWER_MASK) == LVDS_CLKB_POWER_UP) + factor = 25; + } else if (is_sdvo && is_tv) + factor = 20; + + if (clock.m1 < factor * clock.n) + fp |= FP_CB_TUNE; + } + dpll = 0; if (!HAS_PCH_SPLIT(dev)) dpll = DPLL_VGA_MODE_DIS; @@ -4071,7 +4087,6 @@ static int intel_crtc_mode_set(struct drm_crtc *crtc, } if (!has_edp_encoder || intel_encoder_is_pch_edp(&has_edp_encoder->base)) { - I915_WRITE(fp_reg, fp); I915_WRITE(dpll_reg, dpll); /* Wait for the clocks to stabilize. */ |