Hi Sylvain, Thank you for review.
> -----Original Message----- > From: Sylvain Rochet [mailto:[email protected]] > Sent: Saturday, January 24, 2015 1:33 AM > To: Yang, Wenyou > Cc: Ferre, Nicolas; [email protected]; [email protected]; > [email protected]; [email protected]; linux-arm- > [email protected] > Subject: Re: [PATCH 07/12] pm: at91: the standby mode uses the same sram > function as the suspend to memory mode > > Hello Wenyou, > > On Tue, Jan 20, 2015 at 04:17:00PM +0800, Wenyou Yang wrote: > > > > diff --git a/arch/arm/mach-at91/pm.c b/arch/arm/mach-at91/pm.c index > > 691e6db..a1010f0 100644 > > --- a/arch/arm/mach-at91/pm.c > > +++ b/arch/arm/mach-at91/pm.c > (...) > > static int at91_pm_enter(suspend_state_t state) { > > at91_pinctrl_gpio_suspend(); > > > > switch (state) { > > + /* > > + * Suspend-to-RAM is like STANDBY plus slow clock mode, so > > + * drivers must suspend more deeply, the master clock switches > > + * to the clk32k and turns off the main oscillator > > + * > > + * STANDBY mode has *all* drivers suspended; ignores irqs not > > + * marked as 'wakeup' event sources; and reduces DRAM power. > > + * But otherwise it's identical to PM_SUSPEND_ON: cpu idle, and > > + * nothing fancy done with main or cpu clocks. > > + */ > > + case PM_SUSPEND_MEM: > > + case PM_SUSPEND_STANDBY: > (...) > > - case PM_SUSPEND_MEM: > > - /* > > - * Ensure that clocks are in a valid state. > > - */ > > - if (!at91_pm_verify_clocks()) > > - goto error; > (...) > > + if (!at91_pm_verify_clocks()) > > + goto error; > > > (...) > > - case PM_SUSPEND_STANDBY: > > - /* > > - * NOTE: the Wait-for-Interrupt instruction needs to be > > By doing that at91_pm_verify_clocks() is now called for both MEM and STANDBY > targets. > > In my opinion this function is misnamed and should be called > at91_pm_verify_clocks_for_slow_clock_mode(). This function actually checks if > we can safely switch to slow clock mode, if some peripherals are still using > the > master clock, we abort the suspend because we can't suspend in good condition. > Hard unclocking peripherals which ask for a soft stop, like USB controllers, > is > something we should avoid doing. > > This function checks if USB PLL and PLL B are stopped, if PCK0..PCK3 are > stopped too (or just using the 32k clock). If all drivers suspended correctly > this is > the state we expect and we can suspend in a deep state. > > Not this is currently not the case in linux-next, suspend/resume support to > all Atmel > USB drivers (ehci-atmel,ohci-at91,atmel_usba,at91_udc) are in my series: > [PATCHv7 0/6] USB: host: Atmel OHCI and EHCI drivers improvements > <[email protected]> > [PATCHv6 0/5] USB: gadget: atmel_usba_udc: Driver improvements > <[email protected]> > > We are not going to change any clock for STANDBY target, there is no clock to > check, so we don't need to call at91_pm_verify_clocks() for this target. I will change in the next version. Thanks. > > Sylvain Best Regards, Wenyou Yang
