From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qy0-f196.google.com (mail-qy0-f196.google.com [209.85.221.196]) by ozlabs.org (Postfix) with ESMTP id 5AD69DE044 for ; Wed, 27 May 2009 11:01:03 +1000 (EST) Received: by qyk34 with SMTP id 34so7041425qyk.17 for ; Tue, 26 May 2009 18:01:01 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <20090527002530.16740.62502.stgit@terra> <9e4733910905261744j3589ace8wd427ef8a5998eccf@mail.gmail.com> Date: Tue, 26 May 2009 21:01:00 -0400 Message-ID: <9e4733910905261801p130f50afie2c50d5723192d44@mail.gmail.com> Subject: Re: [alsa-devel] [PATCH] Modify mpc5200 AC97 driver to use V9 of spin_event_timeout() From: Jon Smirl To: Timur Tabi Content-Type: text/plain; charset=ISO-8859-1 Cc: linuxppc-dev@ozlabs.org, alsa-devel@alsa-project.org, broonie@sirena.org.uk List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, May 26, 2009 at 8:53 PM, Timur Tabi wrote: > On Tue, May 26, 2009 at 7:44 PM, Jon Smirl wrote: > >> Because Grant didn't want me doing udelay(50) just to delay things in >> order to give the AC97 controller time to initialize. Your function >> lets me loop on cpu_relax() for 50us. > > But udelay() calls HMT_low(), which is like cpu_relax(). Then why did you need to make your routine that calls cpu_relax()? I don't know what goes on in the guts of HMT_low() and cpu_relax(), when you guys decide which one I should use let me know and I can adjust the patch. The hardware needs a minimum 50us pause. It doesn't matter if the pause is more than that. If the CPU has something to keep it busy for a few milliseconds that's fine. > -- > Timur Tabi > Linux kernel developer at Freescale > -- Jon Smirl jonsmirl@gmail.com