From: Jeremy Kerr <jeremy.kerr@canonical.com>
To: Paul Mundt <lethal@linux-sh.org>
Cc: "Russell King - ARM Linux" <linux@arm.linux.org.uk>,
linux-sh@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org,
"Ben Herrenschmidt" <benh@kernel.crashing.org>,
"Sascha Hauer" <s.hauer@pengutronix.de>,
"Lorenzo Pieralisi" <Lorenzo.Pieralisi@arm.com>,
"Vincent Guittot" <vincent.guittot@linaro.org>,
"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Subject: Re: Locking in the clk API
Date: Tue, 11 Jan 2011 22:35:42 +0800 [thread overview]
Message-ID: <201101112235.43061.jeremy.kerr@canonical.com> (raw)
In-Reply-To: <20110111121816.GB774@linux-sh.org>
Hi Paul,
> Again, you are approaching it from the angle that an atomic clock is a
> special requirement rather than the default behaviour.
I'm not considering it a special requirement, but it's still a requirement
(that the called function does not sleep).
The problem with the inverse logic (clk_enable/clk_enable_sleepable) is that
now you've made the caller need to know what kind of clock it has, or might
have one day.
* For clk_enable/clk_enable_atomic, the decision is: is this call in an
atomic context?
* For clk_enable/clk_enable_sleepable, the decision is: might the clock code
have given us a sleeping clock?
Note that it's much easier to guarantee correctness for the first than it is
for the second.
Cheers,
Jeremy
next prev parent reply other threads:[~2011-01-11 14:36 UTC|newest]
Thread overview: 81+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-11 2:16 Locking in the clk API Jeremy Kerr
2011-01-11 3:15 ` Paul Mundt
2011-01-11 4:11 ` Jeremy Kerr
2011-01-11 4:54 ` Paul Mundt
2011-01-20 16:32 ` Ben Dooks
2011-01-20 18:57 ` Russell King - ARM Linux
2011-01-21 3:43 ` Saravana Kannan
2011-01-21 9:31 ` Russell King - ARM Linux
2011-01-11 9:03 ` Sascha Hauer
2011-01-11 9:28 ` Russell King - ARM Linux
2011-01-11 14:34 ` Pavel Machek
2011-01-20 16:29 ` Ben Dooks
2011-01-20 18:56 ` Russell King - ARM Linux
2011-01-20 21:30 ` Nicolas Pitre
2011-01-21 2:06 ` Dima Zavin
2011-01-21 4:12 ` Saravana Kannan
2011-01-21 9:32 ` Russell King - ARM Linux
2011-01-21 21:03 ` Dima Zavin
2011-01-21 21:53 ` Nicolas Pitre
2011-01-21 22:02 ` Russell King - ARM Linux
2011-01-21 22:28 ` Colin Cross
2011-01-21 23:21 ` Benjamin Herrenschmidt
2011-01-21 23:50 ` Nicolas Pitre
2011-01-22 1:35 ` Saravana Kannan
2011-01-22 2:22 ` Colin Cross
2011-01-21 22:29 ` Nicolas Pitre
2011-01-21 23:28 ` Bryan Huntsman
2011-01-11 9:16 ` Russell King - ARM Linux
2011-01-11 9:44 ` Jeremy Kerr
2011-01-11 10:13 ` Paul Mundt
2011-01-11 10:30 ` Jeremy Kerr
2011-01-11 12:18 ` Paul Mundt
2011-01-11 13:52 ` Uwe Kleine-König
2011-01-11 14:35 ` Jeremy Kerr [this message]
2011-01-12 3:25 ` Saravana Kannan
2011-01-12 7:40 ` Uwe Kleine-König
2011-01-12 1:54 ` Saravana Kannan
2011-01-12 2:25 ` Paul Mundt
2011-01-20 16:57 ` Ben Dooks
2011-01-20 16:53 ` Ben Dooks
2011-01-20 16:40 ` Ben Dooks
2011-01-11 10:39 ` Uwe Kleine-König
2011-01-11 10:47 ` Russell King - ARM Linux
2011-01-11 10:56 ` Uwe Kleine-König
2011-01-11 11:15 ` Richard Zhao
2011-01-20 17:02 ` Ben Dooks
2011-01-20 19:08 ` Russell King - ARM Linux
2011-01-21 0:09 ` Jassi Brar
2011-01-21 4:47 ` Jassi Brar
2011-01-21 9:39 ` Russell King - ARM Linux
2011-01-21 10:11 ` Jassi Brar
2011-01-22 4:08 ` Richard Zhao
2011-01-22 5:30 ` Jassi Brar
2011-01-21 7:16 ` Saravana Kannan
2011-01-21 9:40 ` Russell King - ARM Linux
2011-01-27 4:34 ` Saravana Kannan
2011-01-27 8:54 ` Russell King - ARM Linux
2011-01-27 20:30 ` Saravana Kannan
2011-01-27 20:43 ` Russell King - ARM Linux
2011-01-27 21:07 ` Alan Cox
2011-01-27 21:11 ` Russell King - ARM Linux
2011-01-27 21:15 ` Russell King - ARM Linux
2011-01-28 3:29 ` Saravana Kannan
2011-01-28 3:27 ` Saravana Kannan
2011-01-11 12:11 ` Jassi Brar
2011-01-12 2:56 ` Saravana Kannan
2011-01-12 9:03 ` Russell King - ARM Linux
2011-01-15 14:02 ` Christer Weinigel
2011-01-15 14:53 ` Russell King - ARM Linux
2011-01-15 15:03 ` Uwe Kleine-König
2011-01-15 15:15 ` Russell King - ARM Linux
2011-01-15 16:03 ` Uwe Kleine-König
2011-01-15 16:21 ` Russell King - ARM Linux
2011-01-15 16:31 ` Uwe Kleine-König
2011-01-16 6:59 ` Grant Likely
2011-01-15 17:07 ` Christer Weinigel
2011-01-15 17:20 ` Russell King - ARM Linux
2011-01-15 17:44 ` Christer Weinigel
2011-01-15 20:30 ` Russell King - ARM Linux
2011-01-17 1:19 ` Jeremy Kerr
-- strict thread matches above, loose matches on Subject: below --
2011-01-17 1:27 Jeremy Kerr
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