Re: [PATCH 0/8 v7] fix gmbus writes and related issues

Chris Wilson
2012-03-30T12:49:49Z

On Fri, 30 Mar 2012 19:46:35 +0800, Daniel Kurtz <djkurtz@chromium.org> wrote:
> This patchset addresses a couple of issues with the i915 gmbus
> implementation.
>
> v7 adds a final patch to switch to using DRM_ERROR for reporting timeouts.
>
> Daniel Kurtz (8):
> drm/i915/intel_i2c: handle zero-length writes
> drm/i915/intel_i2c: use double-buffered writes
> drm/i915/intel_i2c: always wait for IDLE before clearing NAK
> drm/i915/intel_i2c: use WAIT cycle, not STOP
> drm/i915/intel_i2c: use INDEX cycles for i2c read transactions
> drm/i915/intel_i2c: reuse GMBUS2 value read in polling loop
> drm/i915/intel_i2c: remove POSTING_READ() from gmbus transfers
> drm/i915/intel_i2c: use DRM_ERROR on timeouts

The only two I am still dubious about is 4/8: use WAIT cycle, not STOP,
and 8/8: use DRM_ERROR on timeouts, the rest are
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>

The last is a little debatable, as i2c can be called from userspace (and
other modules) and we have not verified that the adapters we set up
correspond to devices conditions. So I think it is still possible under
normal conditions to hit the error path, so would prefer to keep the log
level as INFO.
-Chris

--
Chris Wilson, Intel Open Source Technology Centre