From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Murthy, Arun R" <arun.r.murthy@gmail.com>
Subject: Re: [PATCH v3] drm/i915: use hrtimer in wait for vblank
Date: Tue, 25 Mar 2014 14:31:24 +0530
Message-ID: <533145E4.6060300@gmail.com>
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 <20140325073029.GV4366@nuc-i3427.alporthouse.com>
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To: Chris Wilson <chris@chris-wilson.co.uk>, Arun R Murthy <arun.r.murthy@intel.com>, daniel.vetter@ffwll.ch, jani.nikula@linux.intel.com, intel-gfx@lists.freedesktop.org, airlied@linux.ie
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On Tuesday 25 March 2014 01:00 PM, Chris Wilson wrote:
> On Tue, Mar 25, 2014 at 11:29:02AM +0530, Arun R Murthy wrote:
>> In wait for vblank use usleep_range, which will use hrtimers instead of
>> msleep. Using msleep(1~20) there are more chances of sleeping for 20ms.
>> Using usleep_range uses hrtimers and hence are precise, worst case will
>> trigger an interrupt at the higher/max timeout.
>>
>> Change-log: On replacing msleep(1) with usleep_range(1000, 2000) we have
>> noticed the time consumed by wait for vblank is ~4ms to ~17ms.
>>
>> Change-Id: I6672e5697b01987a6d069ab06e76d97287b1f7ae
>> Signed-off-by: Arun R Murthy <arun.r.murthy@intel.com>
> No. I feel strongly that we do not want more wait_for_X() with strange
> semantics.
> http://sweng.the-davies.net/Home/rustys-api-design-manifesto

Will revert this additional wait_for_X.
Will update the existing _wait_for as per the kernel documentation for 
timers.

Thanks and Regards,
Arun R Murthy
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