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From: "Murthy, Arun R" <arun.r.murthy@gmail.com>
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
Subject: Re: [PATCH v3] drm/i915: use hrtimer in wait for vblank
Date: Tue, 25 Mar 2014 14:31:24 +0530	[thread overview]
Message-ID: <533145E4.6060300@gmail.com> (raw)
In-Reply-To: <20140325073029.GV4366@nuc-i3427.alporthouse.com>

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
------------------

      reply	other threads:[~2014-03-25  9:02 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-03-25  5:59 [PATCH v3] drm/i915: use hrtimer in wait for vblank Arun R Murthy
2014-03-25  7:30 ` Chris Wilson
2014-03-25  9:01   ` Murthy, Arun R [this message]

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