Re: [PATCH 02/09] drm/i915: try to train DP even harder

Daniel Vetter
2012-07-12T14:58:12Z

On Fri, Jun 29, 2012 at 04:03:34PM -0300, Paulo Zanoni wrote:
> From: Paulo Zanoni <paulo.r.zanoni@intel.com>
>
> While debugging Haswell link train failures I observed that we never
> try the maximum voltage configuration more than once consecutively. We
> start the training, the monitor keeps telling us to increase the
> voltage, then when we reach the maximum we just go back to the start
> (because of the "memset" above "voltage_tries = 0"). When we reach
> this point, we keep alternating between the maximum and the minimum
> voltages until we give up.
>
> The DP spec suggests that we should try the same voltage 5 times
> before giving up. This patch makes us try the maximum voltage at
> least 5 times before going back to the minimum voltages.
>
> This patch does not fix any particular bug I'm aware of.
>
> Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>

Gosh, this is the most convoluted loop flattening code I've ever seen.
Patch queued for -next, thanks.
-Daniel
--
Daniel Vetter
Mail: daniel@ffwll.ch
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