From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sascha Hauer Subject: Re: imx-ssi fixes Date: Thu, 8 Apr 2010 17:51:13 +0200 Message-ID: <20100408155113.GM3688@pengutronix.de> References: <1270719086-23453-1-git-send-email-s.hauer@pengutronix.de> <20100408144750.GC14241@sirena.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [92.198.50.35]) by alsa0.perex.cz (Postfix) with ESMTP id B3FD110397D for ; Thu, 8 Apr 2010 17:51:13 +0200 (CEST) Content-Disposition: inline In-Reply-To: <20100408144750.GC14241@sirena.org.uk> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: alsa-devel-bounces@alsa-project.org Errors-To: alsa-devel-bounces@alsa-project.org To: Mark Brown Cc: alsa-devel@alsa-project.org, Valentin Longchamp List-Id: alsa-devel@alsa-project.org On Thu, Apr 08, 2010 at 03:47:50PM +0100, Mark Brown wrote: > On Thu, Apr 08, 2010 at 11:31:23AM +0200, Sascha Hauer wrote: > > > Here are some bugfix patches for the imx-ssi driver. It should also fix > > the problems reported in FIQ mode. > > Applied all three, thanks - the hrtimer stuff works an awful lot better > than the vanilla timer stuff did. It's a shame I hadn't noticed that > hrtimers did manage to give better resolution on i.MX when I looked into > this previously. > > It'd be good if you could look into the timer sync issue - doing > something like deferring the timer by a proportion of a period if > the period hasn't elapsed ought to cover it. I'll look into it. I'm thinking of - busywaiting if the current period hasn't elapsed (should rarely if ever the case since the fiq works reliable and the timer interrupt introduces additional delays. - calculate the next callback time based on the current offset. If you haven't pushed the patches forward it would be good to delay the hrtimer patch a bit. I managed to shoot the system down while playing audio with a hackbench 10. This doesn't happen without the hrtimer patch. This may be related to the problem Valentin reported. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |