Messages in this thread | | | From | Chris Wilson <> | Subject | Re: [PATCH 08/13 v4] drm/i915/intel_i2c: handle zero-length writes | Date | Wed, 28 Mar 2012 12:39:12 +0100 |
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On Wed, 28 Mar 2012 19:32:27 +0800, Daniel Kurtz <djkurtz@chromium.org> wrote: > Unfortunately there is a bug in both my original patch (it wasn't > incrementing loop), and in your suggested cleanup (it always > decrements len, even when it is already 0... or if the loop test > fails). How about the following; despite its pythonic nature, it > always completes with len holding the number of bytes remaining. > > val = loop = 0; > while (len && loop < 4) { > val |= *buf++ << (8 * loop++); > len -= 1; > }
I'm getting over my aversion ;-)
As we are here, have you considered doing an optimised u32 variant whilst len >= 4, which should be reasonably common during EDID transfer. Though I am not sure if that loop is merely in the noise compared to the rest of the mmio. -Chris
-- Chris Wilson, Intel Open Source Technology Centre
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