From mboxrd@z Thu Jan 1 00:00:00 1970 From: Simon Farnsworth Subject: Re: [PATCH] drm/radeon: Move pageflip request from vblank IRQ to ioctl Date: Wed, 6 Jul 2011 18:44:30 +0100 Message-ID: <201107061844.30779.simon.farnsworth@onelan.co.uk> References: <1309969743-10318-1-git-send-email-simon.farnsworth@onelan.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from claranet-outbound-smtp05.uk.clara.net (claranet-outbound-smtp05.uk.clara.net [195.8.89.38]) by gabe.freedesktop.org (Postfix) with ESMTP id F20649E745 for ; Wed, 6 Jul 2011 10:44:32 -0700 (PDT) In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org Errors-To: dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org To: Jerome Glisse Cc: dri-devel@lists.freedesktop.org List-Id: dri-devel@lists.freedesktop.org On Wednesday 6 July 2011, Jerome Glisse wrote: > On Wed, Jul 6, 2011 at 12:29 PM, Simon Farnsworth > > > In particular, I'm a bit hazy about what the fence in pageflip is > > doing - I assume it's there to synchronize drawing and scanout, so > > that I don't flip to a buffer that's still being drawn on by the GPU. > > > In my view all the fence stuff become useless as when the irq handler > call we know we can unpin previous scanout (the crtc is scanning from > new buffer). Otherwise it looks good (beside the optimization of > computing how much time we should sleep instead of while msleep but > this can be left as a latter patch). > So, I don't know why this makes a difference - but removing the fence completely causes the second pageflip to stall forever. Changing it for a radeon_bo_wait on the new frontbuffer still results in infinite stalls. I've noticed a couple of minor issues in the patch anyway (a redundant lock/unlock pair left in, and I should be using usleep_range not msleep, given that I want to wait for less than a millisecond normally), so I'll respin anyway. -- Simon Farnsworth Software Engineer ONELAN Limited http://www.onelan.com/