Messages in this thread | | | From | Chris Wilson <> | Subject | Re: [PATCH 13/13 v4] drm/i915/intel_i2c: reuse GMBUS2 value read in polling loop | Date | Wed, 28 Mar 2012 12:44:59 +0100 |
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On Wed, 28 Mar 2012 19:39:17 +0800, Daniel Kurtz <djkurtz@chromium.org> wrote: > On Wed, Mar 28, 2012 at 3:02 AM, Chris Wilson <chris@chris-wilson.co.uk> wrote: > > Might as well shave this read as well. > > Do you know why POSTING_READ() was there in the first place? > As far as I can tell, these are used to ensure memory barriers are > inserted between a group of writes, and subsequent reads to memory > mapped io registers. > However, the normal I915_READ() and I915_WRITE() macros already call > readl() / writel(), which already have an explicit mb(). > So, can we just get rid of all of them, or am I missing something?
They can go. They were there just as paranoia to make sure the writes were flushed before any timing delays and across loops. Once the code settled I never took the liberty of removing them. -Chris
-- Chris Wilson, Intel Open Source Technology Centre
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