From: Mark Brown <broonie@opensource.wolfsonmicro.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Jean Delvare <khali@linux-fr.org>,
Sven-Thorsten Dietrich <sven@thebigcorporation.com>,
Leon Woestenberg <leon.woestenberg@gmail.com>,
linux-i2c@vger.kernel.org,
rt-users <linux-rt-users@vger.kernel.org>,
"Ben Dooks (embedded platforms)" <ben-linux@fluff.org>,
Peter Zijlstra <peterz@infradead.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: yield() in i2c non-happy paths hits BUG under -rt patch
Date: Mon, 16 Nov 2009 15:56:06 +0000 [thread overview]
Message-ID: <20091116155606.GC29479@sirena.org.uk> (raw)
In-Reply-To: <alpine.LFD.2.00.0911132139560.24119@localhost.localdomain>
On Fri, Nov 13, 2009 at 11:03:39PM +0100, Thomas Gleixner wrote:
> Q: Why put people yield() into their code ?
> A: Because:
> - it is less nasty than busy waiting for a long time
> - it works better
...
> I can see the idea of using yield() to let other tasks making progress
> in situations where the hardware is a design failure as well,
> e.g. bitbang devices. But if we have to deal with hardware which is
> crap by design yield() is the worst of all answers simply due to its
> horrible semantics.
What other options are there available for the first case (which is
often why things work better with the use of yield) that don't involve
sleeps, or is the idea that in situations like this drivers should
always sleep?
next prev parent reply other threads:[~2009-11-16 15:56 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <c384c5ea0911071101u7415d37o2611c542e5fae309@mail.gmail.com>
[not found] ` <20091107210147.3e754278@hyperion.delvare>
[not found] ` <4AF7148C.9090706@thebigcorporation.com>
[not found] ` <20091112211255.09cd884a@hyperion.delvare>
2009-11-13 22:03 ` yield() in i2c non-happy paths hits BUG under -rt patch Thomas Gleixner
2009-11-14 18:02 ` Jean Delvare
2009-11-16 15:56 ` Mark Brown [this message]
2009-11-18 0:50 ` Leon Woestenberg
2009-11-18 1:05 ` Alan Cox
2009-11-18 16:28 ` Leon Woestenberg
2009-11-18 16:52 ` Jean Delvare
2009-11-18 20:36 ` Thomas Gleixner
2009-11-19 12:05 ` Jean Delvare
2009-11-19 12:59 ` Alan Cox
2009-11-19 13:06 ` Peter Zijlstra
2009-11-19 14:00 ` Jean Delvare
2009-11-19 14:15 ` Peter Zijlstra
2009-11-19 13:11 ` Thomas Gleixner
2009-11-19 13:21 ` Peter Zijlstra
2009-11-19 13:22 ` Thomas Gleixner
2009-11-19 13:18 ` Peter Zijlstra
2009-11-18 20:46 ` [PATCH] cleanup sched_yield (sys)call nesting Sven-Thorsten Dietrich
2009-11-18 20:56 ` Thomas Gleixner
2009-11-18 21:04 ` Sven-Thorsten Dietrich
2009-11-18 21:34 ` Thomas Gleixner
2009-11-19 4:48 ` Sven-Thorsten Dietrich
2009-11-19 10:36 ` Thomas Gleixner
2009-11-19 3:20 ` Ingo Molnar
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