From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Dooks Date: Thu, 20 Jan 2011 17:02:55 +0000 Subject: Re: Locking in the clk API Message-Id: <4D386ABF.9060908@fluff.org> List-Id: References: <201101111016.42819.jeremy.kerr@canonical.com> <20110111091607.GI12552@n2100.arm.linux.org.uk> <201101111744.59712.jeremy.kerr@canonical.com> <20110111103929.GN24920@pengutronix.de> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable To: linux-arm-kernel@lists.infradead.org On 11/01/11 11:15, Richard Zhao wrote: > 2011/1/11 Uwe Kleine-K=F6nig : [snip] > A well running board will not enable/disable PLLs frequently. It don't > make sense. PLLs are normally disabled on request to enter low power > mode, rather not because all their child clocks are disabled. So we > don't have to consider the time here. I'd rather see that if all child clocks are disabled the PLL is powered down then. It means PLLs _could_ be left running even when power-down mode is selected because the system still thinks that a peripheral is using them. If you want to make it so that each low-power mode has to work out what PLLs need to be disabled and then re-enabled makes me want to be sick. Hiding this stuff behind specific implementations is a recipe for disaster.