From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Vetter Subject: Re: [PATCH] drm/i915: Fix single msg gmbus_xfers writes Date: Mon, 13 Feb 2012 23:26:23 +0100 Message-ID: <20120213222623.GN5301@phenom.ffwll.local> References: <1328817797-4026-1-git-send-email-bleung@chromium.org> <20120213203838.GM5301@phenom.ffwll.local> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-wi0-f177.google.com (mail-wi0-f177.google.com [209.85.212.177]) by gabe.freedesktop.org (Postfix) with ESMTP id 62DCA9E917 for ; Mon, 13 Feb 2012 14:26:10 -0800 (PST) Received: by wico1 with SMTP id o1so4418247wic.36 for ; Mon, 13 Feb 2012 14:26:09 -0800 (PST) Content-Disposition: inline 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: Chris Wilson Cc: linux-kernel@vger.kernel.org, djkurtz@chromium.org, dri-devel@lists.freedesktop.org, Benson Leung List-Id: dri-devel@lists.freedesktop.org On Mon, Feb 13, 2012 at 09:49:35PM +0000, Chris Wilson wrote: > On Mon, 13 Feb 2012 21:38:38 +0100, Daniel Vetter wrote: > > This here looks like just a white-space change. But your commit message > > sounds like it's not jsut write's that are affected by this issue and need > > to be fixed. Can you please clear up this for easily confused me? > > It makes the write path similar to the read path. I admit to overlooking > the single write message as everything I saw was always a write followed > by a read. The patch looks correct, but I need to stare at it a bit more > before I r-b. > > However, the outstanding issue is that we need to separate the gmbus > i2c adapter from the gpio i2c adapter in order for the pairing to work > with the expectations of the i2c core. There's another patch floating on dri-devel to add a gmbus_mutex. The issue it tries to avoid is that multiple users corrupting each anothers state when using the single gmbus controller. See "[PATCH] [PATCH] drm/i915: Fix race condition in accessing GMBUS". Or have you thought of another interaction that we need to sort out? -Daniel -- Daniel Vetter Mail: daniel@ffwll.ch Mobile: +41 (0)79 365 57 48