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drm/i915: Use a loop for the "three times for luck" DPLL procedure

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The magic "enable the  DPLL three times" sequence feels like it
deserves a loop.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170601143619.27840-4-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
This commit is contained in:
Ville Syrjälä 2017-06-01 17:36:15 +03:00
parent da1d0e2655
commit bb408dd2b2
1 changed files with 6 additions and 9 deletions
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15
drivers/gpu/drm/i915/intel_display.c
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@ -1550,6 +1550,7 @@ static void i9xx_enable_pll(struct intel_crtc *crtc)
struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
i915_reg_t reg = DPLL(crtc->pipe);
u32 dpll = crtc->config->dpll_hw_state.dpll;
int i;
assert_pipe_disabled(dev_priv, crtc->pipe);
@ -1596,15 +1597,11 @@ static void i9xx_enable_pll(struct intel_crtc *crtc)
}
/* We do this three times for luck */
I915_WRITE(reg, dpll);
POSTING_READ(reg);
udelay(150); /* wait for warmup */
I915_WRITE(reg, dpll);
POSTING_READ(reg);
udelay(150); /* wait for warmup */
I915_WRITE(reg, dpll);
POSTING_READ(reg);
udelay(150); /* wait for warmup */
for (i = 0; i < 3; i++) {
I915_WRITE(reg, dpll);
POSTING_READ(reg);
udelay(150); /* wait for warmup */
}
}
/**