From mboxrd@z Thu Jan 1 00:00:00 1970 From: Simon Farnsworth Subject: Re: [PATCH 1/4] introduce intel_ring_buffer structure Date: Wed, 19 May 2010 18:33:31 +0100 Message-ID: <201005191833.31825.simon.farnsworth@onelan.com> References: <1273108805-1354-1-git-send-email-nanhai.zou@intel.com> <201005191000.11272.simon.farnsworth@onelan.com> <87tyq3esrj.fsf@pollan.anholt.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from claranet-outbound-smtp04.uk.clara.net (claranet-outbound-smtp04.uk.clara.net [195.8.89.37]) by gabe.freedesktop.org (Postfix) with ESMTP id F145D9E7BE for ; Wed, 19 May 2010 10:33:38 -0700 (PDT) In-Reply-To: <87tyq3esrj.fsf@pollan.anholt.net> 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: Eric Anholt Cc: "intel-gfx@lists.freedesktop.org" List-Id: intel-gfx@lists.freedesktop.org On Wednesday 19 May 2010, Eric Anholt wrote: > On Wed, 19 May 2010 10:00:10 +0100, Simon Farnsworth wrote: > > Bear in mind that I don't have to use VAAPI to call your ioctl; I can > > write evil code that calls it directly. On the other hand, you can't > > remove the ioctl later - users will want to use older VAAPI versions > > with new kernels, so that they can upgrade without too much fear of > > regression. > > OK, now you're going over the top. The GPU can't schedule[1], is turing > complete, and you hand it programs. You can hang it with or without his > interface. If you don't want to be able to do that, then don't let > non-root use the DRI. > Fair enough, and my apologies for going overboard - my intended point is that just because VAAPI is the only planned user of this ioctl doesn't mean that it's OK to get the userspace/kernel interface wrong. -- Simon Farnsworth Software Engineer ONELAN Limited http://www.onelan.com/