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drm/i915: Wait for cdclk change to occure when going for 400MHz

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VLV Punit doesn't support the 400MHz cdclk option, so we bypass the
Punit and poke at CCK directly. However we forgot to wait for the
frequeency change to complete. Poll the CCK clock status to make sure
the clock has changed before we fire up any pipes.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Ville Syrjälä 2014-06-13 13:37:52 +03:00 committed by Daniel Vetter
parent e37c67a1c5
commit a877e8015c
1 changed files with 5 additions and 0 deletions
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5
drivers/gpu/drm/i915/intel_display.c
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@ -4519,6 +4519,11 @@ static void valleyview_set_cdclk(struct drm_device *dev, int cdclk)
val &= ~DISPLAY_FREQUENCY_VALUES;
val |= divider;
vlv_cck_write(dev_priv, CCK_DISPLAY_CLOCK_CONTROL, val);
if (wait_for((vlv_cck_read(dev_priv, CCK_DISPLAY_CLOCK_CONTROL) &
DISPLAY_FREQUENCY_STATUS) == (divider << DISPLAY_FREQUENCY_STATUS_SHIFT),
50))
DRM_ERROR("timed out waiting for CDclk change\n");
mutex_unlock(&dev_priv->dpio_lock);
}