On Fri, Mar 22, 2013 at 04:48:11PM +0100, Stephen Warren wrote: > On 03/22/2013 05:54 AM, Peter De Schrijver wrote: > > The PLL code relies on udelay() which is not available when CCF is > > initialized. Hence we can't enable any PLL during this phase. > > > > Signed-off-by: Peter De Schrijver <pdeschrijver@xxxxxxxxxx> > > > > -- > > > > Stephen, > > > > Can you confirm this is ok for the audio drivers? > > > > We used to be lucky that this has worked up to now, but I will introduce some > > changes to the pll lock check code which cause this to fail due to the > > slight differences in timing. > > No, this won't work for the audio drivers; they assume the clock is > enabled when they start. > > This assumption was made long ago. I know drivers are supposed to assume > that clocks are disabled when they're probed, but historically that > wasn't always the case, so if the audio drivers assumed that, and then > did clk_enable() as the first thing, they got a warning due to the > enabling an already enabled clock and/or later attempts to disable the That should be ok. You can enable a clock more than once. > clocks wouldn't actually disable them. Perhaps this has changed now, but > either way, audio driver changes would be needed to support this change. > But indeed, the clock won't be disabled then when the driver does clk_disable(). The reference count will just be decremented. That's however not a functional problem, just not optimal from a power consumption point of view. So we could change the drivers first and keep the clocks disabled at boottime in a second phase. > Perhaps this is due to initializing the Tegra clock driver in the > machine descriptor's init_irq function, rather than in the init_machine > function? Can this be moved? Maybe. But we need the clockframework before the timers are initialized... So I have to check the dependencies. Cheers, Peter. -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
