linux-kernel - Re: [PATCH 2/2] drm/fence: allow fence waiting to be interrupted by userspace

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Message-ID: <20160815135024.GF6232@phenom.ffwll.local>
Date:	Mon, 15 Aug 2016 15:50:24 +0200
From:	Daniel Vetter <daniel@...ll.ch>
To:	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>
Cc:	Gustavo Padovan <gustavo@...ovan.org>,
	dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
	Daniel Stone <daniels@...labora.com>,
	Daniel Vetter <daniel.vetter@...ll.ch>,
	Rob Clark <robdclark@...il.com>,
	Greg Hackmann <ghackmann@...gle.com>,
	John Harrison <John.C.Harrison@...el.com>,
	laurent.pinchart@...asonboard.com, seanpaul@...gle.com,
	marcheu@...gle.com, m.chehab@...sung.com,
	Sumit Semwal <sumit.semwal@...aro.org>,
	Gustavo Padovan <gustavo.padovan@...labora.co.uk>
Subject: Re: [PATCH 2/2] drm/fence: allow fence waiting to be interrupted by
 userspace

On Mon, Aug 15, 2016 at 12:15:32PM +0200, Maarten Lankhorst wrote:
> Op 11-08-16 om 20:39 schreef Gustavo Padovan:
> > From: Gustavo Padovan <gustavo.padovan@...labora.co.uk>
> >
> > If userspace is running an synchronously atomic commit and interrupts the
> > atomic operation during fence_wait() it will hang until the timer expires,
> > so here we change the wait to be interruptible so it stop immediately when
> > userspace wants to quit.
> >
> > Also adds the necessary error checking for fence_wait().
> >
> > v2: Comment by Daniel Vetter
> > 	- Add error checking for fence_wait()
> >
> > v3: Rebase on top of new atomic noblocking support
> Meh, I don't like the swapped parameter much, couldn't we infer it from intr? or rename intr to swapped?
> If we're not swapped yet, we should always wait interruptibly. When swapped, never..

Yeah this seems somewhat silly tbh, but then I guess making those waits
interruptible is indeed somewhat nice.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch