Hello Am Freitag, den 26.10.2012, 23:01 +0300 schrieb Felipe Balbi: > Hi, > > On Fri, Oct 26, 2012 at 03:19:13PM +0200, Tim Niemeyer wrote: > > Adds support for configuring the omap-gpio driver use autosuspend for > > runtime power management. This can reduce the latency in using it by > > not suspending the device immediately on idle. If another access takes > > place before the autosuspend timeout (2 secs), the call to resume the > > device can return immediately saving some save/ restore cycles. > > > > This removes also the bank->mod_usage counter, because this is already > > handled in pm_runtime. > > > > I use a gpio to monitor a spi transfer which occurs every 250µs. The > > suspend overhead is to high, so almost every second transfer is lost. > > This patch fixes that. > > > > Signed-off-by: Tim Niemeyer <tim.niemeyer@xxxxxxxxxxxxx> > > --- > > drivers/gpio/gpio-omap.c | 81 ++++++++++++++++++++++++--------------------- > > 1 files changed, 43 insertions(+), 38 deletions(-) > > > > diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c > > index 94cbc84..708d5a9 100644 > > --- a/drivers/gpio/gpio-omap.c > > +++ b/drivers/gpio/gpio-omap.c > > @@ -31,6 +31,7 @@ > > #include <asm/mach/irq.h> > > > > #define OFF_MODE 1 > > +#define GPIO_AUTOSUSPEND_TIMEOUT 2000 > > something just hit me... If you keep timeout at 2000 ms and you hook > this up to an IRQ line, it's very unlikely GPIO will ever sleep. > > Why did you choose 2000 ms ? Arbitrary value ? Got it from the spi driver (27b5284cfbe187732ebb184b03ea693f44837f9d). I have no problem with reducing this. As i don't know how much power-overhead the suspend needs, what do you think is a good value in terms of power-saving? -- Tim Niemeyer Corscience GmbH & Co. KG Henkestr. 91 D-91052 Erlangen Germany e-mail: tim.niemeyer@xxxxxxxxxxxxx Internet: www.corscience.de -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
