From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Vetter Subject: Re: [PATCH 28/50] drm: Remove DRM_WAIT_ON from all drivers Date: Wed, 18 Dec 2013 09:25:19 +0100 Message-ID: <20131218082519.GC26371@phenom.ffwll.local> References: <1386758111-3446-1-git-send-email-daniel.vetter@ffwll.ch> <1386758111-3446-29-git-send-email-daniel.vetter@ffwll.ch> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-ee0-f52.google.com (mail-ee0-f52.google.com [74.125.83.52]) by gabe.freedesktop.org (Postfix) with ESMTP id 265C811DC6B for ; Wed, 18 Dec 2013 00:24:27 -0800 (PST) Received: by mail-ee0-f52.google.com with SMTP id d17so3361533eek.11 for ; Wed, 18 Dec 2013 00:24:25 -0800 (PST) Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dri-devel-bounces@lists.freedesktop.org Errors-To: dri-devel-bounces@lists.freedesktop.org To: Dave Airlie Cc: Daniel Vetter , Thomas Hellstrom , DRI Development List-Id: dri-devel@lists.freedesktop.org On Wed, Dec 18, 2013 at 11:39:27AM +1000, Dave Airlie wrote: > On Wed, Dec 11, 2013 at 8:34 PM, Daniel Vetter wrote: > > Since this is all old ums stuff (including the one in the radeon > > driver) I've just tried to perfectly replicate the existing semantics. > > > > Reinventing wait queue code with semantics that differ from all the > > standard linux wait functions is just hairy, so now we can get rid of > > this and so make sure it'll never again be used. > > > > Oh and: via futexes ... *shudder* > > This one worries me, I've had numerous attempts to rip this out in the > past and they always changed semantics on some devices and broke > stuff. > > The sneaky timeout is essential for a lot of the hardware > > http://marc.info/?l=dri-devel&m=111383274225047&w=1 > > So I think I'd like a few more people to review this one before I go > near it again :-) Oh, and I've thought the only tricky stuff is mapping the errno's correctly. I think if we have such cases of racy drivers then the right thing to do is to shovel this macro into drivers and slap a big comment about signalling races on top of that code. Thomas report doesn't say so, but I guess it's for via. Thomas, do you still have a vague recollection of what this has been about? Dave, do you want me to just respin this one with via left as-is (and the macro pushed into the via driver)? Thanks, Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch