Date: Wed, 23 May 2007 21:28:16 +0200
From: Ingo Molnar <mingo@elte.hu>
To: Rene Herman <rene.herman@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>, LKML <linux-kernel@vger.kernel.org>,
       Alan Cox <alan@lxorguk.ukuu.org.uk>, Jeff Garzik <jeff@garzik.org>,
       Pekka Enberg <penberg@cs.helsinki.fi>
Subject: Re: [PATCH] CDROM: replace jiffies busyloop with msleep
Message-ID: <20070523192816.GA16603@elte.hu>
References: <1179829525.12708.118.camel@chaos> <46548ADB.60207@gmail.com>
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* Rene Herman <rene.herman@gmail.com> wrote:

> The trouble there is that unless you poll the bloody thing like mad 
> too much of the Q subchannels passes below you and you need a huge 
> number of retries to get anything out of it. I noticed when I started 
> adding audio bits that the driver took full seconds to complete some 
> audio requests while the old driver was snappy in that regard. When I 
> replaced our sleeping loop with a busy-wait same as the original the 
> snappyness returned and moreover, reading the TOC from the CD went 
> from something close to a minute to approximately a second. Thought 
> that minute was just because I was dealing with an old junk 1-speed 
> drive...

ouch ...

then i guess the right approach is to not use jiffies but to use a 
calculated number of udelay(10) calls or so.

	Ingo
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