From mboxrd@z Thu Jan 1 00:00:00 1970 From: mturquette@ti.com (Mike Turquette) Date: Sun, 6 May 2012 16:49:58 -0700 Subject: common clock framework In-Reply-To: References: <20120504082110.GB16535@pengutronix.de> Message-ID: <20120506234958.GA14559@gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 20120505-13:33, Raul Xiong wrote: > 2012/5/5 Turquette, Mike > > Bad news: lockdep gets cranky about possible deadlocks due to holding > > prepare_lock and then trying to hold it again in a rate-change > > notifier handler (from OMAP's regulator code). Specifically > > > > Glad to see common clock framework will support DVFS. Can we use different > spinlock for different clocks with different lockdep lock classes to avoid > the dead lock and lockdep warnings? I understand that different lockdep classes could allow for nested locking, but I don't have a good idea of how that would actually be implemented. Could you elaborate a bit more? In the mean time I'm looking at some different locking semantics that don't involve lockdep class mangling, just a more fine-grained approach to locking exactly what we want. Regards, Mike