From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Wilson Subject: Re: [PATCH 2/2] drm/i915: Warn if ring tail is not qword aligned Date: Mon, 26 Nov 2012 17:46:48 +0000 Message-ID: References: <1353934099-18685-1-git-send-email-ville.syrjala@linux.intel.com> <1353934099-18685-3-git-send-email-ville.syrjala@linux.intel.com> <453bf0$6k5283@azsmga001.ch.intel.com> <20121126174016.GB20128@intel.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0323787190==" Return-path: Received: from mga03.intel.com (mga03.intel.com [143.182.124.21]) by gabe.freedesktop.org (Postfix) with ESMTP id 9C949E6299 for ; Mon, 26 Nov 2012 09:47:06 -0800 (PST) In-Reply-To: <20121126174016.GB20128@intel.com> 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 Cc: intel-gfx@lists.freedesktop.org List-Id: intel-gfx@lists.freedesktop.org --===============0323787190== Content-Type: text/plain On Mon, 26 Nov 2012 19:40:16 +0200, Ville Syrjälä wrote: > On Mon, Nov 26, 2012 at 04:25:47PM +0000, Chris Wilson wrote: > > On Mon, 26 Nov 2012 14:48:19 +0200, ville.syrjala@linux.intel.com wrote: > > > From: Ville Syrjälä > > > > > > Ringbuffer tail pointer must be qword aligned. Warn if someone > > > makes a mistake and forgets to pad the ring when the commands > > > inserted into the ring don't align to qword naturally. > > > > The assertion should be that we wrote precisely the number of dwords we > > declared in intel_ring_begin(). Which is one of the important factors to > > check whenever reviewing such code. This assertion (which should be a > > BUG_ON) is no substitute for such review. > > Yeah. I was considering adding some reserved_space field to the ring, > populate it in ring_begin(), and and make sure it was correctly > consumed at ring_advance(). If you think that sounds good, I can cook > up a patch for it. To be honest, I was thinking of a firing squad for the author and reviewers of any such patch that gets intel_ring_begin()..end() wrong. -Chris -- Chris Wilson, Intel Open Source Technology Centre --===============0323787190== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/intel-gfx --===============0323787190==--