From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Wilson Subject: Re: [PATCH] drm/i915: Only insert the mb() before updating the fence parameter Date: Tue, 09 Oct 2012 12:26:57 +0100 Message-ID: <6c3329$6lntgg@orsmga002.jf.intel.com> References: <1349771938-18887-1-git-send-email-chris@chris-wilson.co.uk> <20121009095412.GC5844@phenom.ffwll.local> <275ffc$6tlakm@fmsmga002.fm.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by gabe.freedesktop.org (Postfix) with ESMTP id DD7579EB76 for ; Tue, 9 Oct 2012 04:27:04 -0700 (PDT) In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org Errors-To: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org To: Daniel Vetter Cc: intel-gfx@lists.freedesktop.org List-Id: intel-gfx@lists.freedesktop.org On Tue, 9 Oct 2012 13:14:09 +0200, Daniel Vetter wrote: > One thing I wonder is whether we miss any barrier between the wc > writes to the ringbuffer and the tail update. If that's the case I > wonder where all the bug reports are ... Ditto. I've often wondered how we get away without a wmb() there... > Last one: Which machines blow up when you drop that mb()? pnv, though that's the only non-LLC I've been testing with the incomplete patch so I can't say it is limited to that machine. -Chris -- Chris Wilson, Intel Open Source Technology Centre