From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Vetter Subject: Re: [PATCH 1/4] introduce intel_ring_buffer structure Date: Mon, 17 May 2010 19:42:33 +0200 Message-ID: <20100517174232.GA3546@viiv.ffwll.ch> References: <1273108805-1354-1-git-send-email-nanhai.zou@intel.com> <20100511222425.GB3930@viiv.ffwll.ch> <41EFD7A46E18724CAB128DAD007334800544E081BA@shsmsx502.ccr.corp.intel.com> <20100514174350.GC32469@stephanie.nicotinebsd.org> <41EFD7A46E18724CAB128DAD0073348006A62B749A@shsmsx502.ccr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail.ffwll.ch (cable-static-49-187.intergga.ch [157.161.49.187]) by gabe.freedesktop.org (Postfix) with ESMTP id E70329E74C for ; Mon, 17 May 2010 10:41:51 -0700 (PDT) Content-Disposition: inline In-Reply-To: <41EFD7A46E18724CAB128DAD0073348006A62B749A@shsmsx502.ccr.corp.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 To: "Zou, Nanhai" Cc: "Anholt, Eric" , Intel GFX List-Id: intel-gfx@lists.freedesktop.org Hi On Mon, May 17, 2010 at 09:43:02AM +0800, Zou, Nanhai wrote: > You may check how user space works in VAAPI code, if you have an Ironlake system. > We have install guide at http://intellinuxgraphics.org/h264.html. > We have some customer requests for H.264 decoding, so we point to an > early kernel and a similar patch on that page. I'll try this out. But likely takes a while till I get around - there's enough other stuff going on to keep me busy. > Actually no additional synchronize was add to user space, after BSD > decoding is done, we map the BSD output for media pipe input command > stream, at this point kernel will wait BSD decoding done before it begin > media pipe. > > so unprivileged client can not damage GPU with this. > > Though this is not the most efficient way to do the work, > > One of our optimize plan is to have double ring buffer for H.264 > decoding later, e.g. while BSD is decoding to one buffer, media pipe may > consume another buffer, > > So media and BSD ring can work in parallel. Once we begin to do that, we > may need to design a better synchronize method. Well, that's exactly the problem. You simply can't optimize a kernel interface once it's in use. And if you try to, your users will get the pitchforks and scream bloody murder trying to get you ;) So we need to get these patches right (at least the semantics of the interface) beforehand. > Thanks > Zou Nan hai Yours, Daniel -- Daniel Vetter Mail: daniel@ffwll.ch Mobile: +41 (0)79 365 57 48