From: Ville Syrjälä Date: Wed, 6 May 2015 11:28:57 +0000 (+0300) Subject: drm/i915: Add missing POSTING_READ()s to BXT dbuf enable sequence X-Git-Tag: Ubuntu-5.4-5.4.0-11.14~12009^2~54^2~66 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=22e02c0b4bc87c94895b1f4cb25ee705d5687cb1;p=mirror_ubuntu-focal-kernel.git drm/i915: Add missing POSTING_READ()s to BXT dbuf enable sequence 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 Signed-off-by: Ville Syrjälä Reviewed-by: Imre Deak Signed-off-by: Daniel Vetter --- diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 8e21e2358c0a..5c2047b6127b 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)