From: Ville Syrjälä <[email protected]> Do a POSTING_READ() between the DBUF_CTL register write and the udelay() to make sure we really wait after the register write has happened.
Spotted while reviewing Damien's SKL cdclk patch which had the POSTING_READ()s. Cc: Imre Deak <[email protected]> Signed-off-by: Ville Syrjälä <[email protected]> --- drivers/gpu/drm/i915/intel_display.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 8e21e23..5c2047b 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -5482,6 +5482,8 @@ void broxton_init_cdclk(struct drm_device *dev) broxton_set_cdclk(dev, 624000); I915_WRITE(DBUF_CTL, I915_READ(DBUF_CTL) | DBUF_POWER_REQUEST); + POSTING_READ(DBUF_CTL); + udelay(10); if (!(I915_READ(DBUF_CTL) & DBUF_POWER_STATE)) @@ -5493,6 +5495,8 @@ void broxton_uninit_cdclk(struct drm_device *dev) struct drm_i915_private *dev_priv = dev->dev_private; I915_WRITE(DBUF_CTL, I915_READ(DBUF_CTL) & ~DBUF_POWER_REQUEST); + POSTING_READ(DBUF_CTL); + udelay(10); if (I915_READ(DBUF_CTL) & DBUF_POWER_STATE) -- 2.0.5 _______________________________________________ Intel-gfx mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/intel-gfx
