On Thu, 01 Jun 2017, ville.syrjala@xxxxxxxxxxxxxxx wrote:
> From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
>
> The magic "enable the DPLL three times" sequence feels like it
> deserves a loop.
I think the copy-paste unrolled loop is more fun. ;)
Reviewed-by: Jani Nikula <jani.nikula@xxxxxxxxx>
> Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/i915/intel_display.c | 15 ++++++---------
> 1 file changed, 6 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 4e3c64ed4131..2b112229b5b2 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -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 */
> + }
> }
>
> /**
--
Jani Nikula, Intel Open Source Technology Center
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