Mike Chan <mike@xxxxxxxxxxx> writes: > On Wed, Apr 21, 2010 at 5:07 PM, Kevin Hilman > <khilman@xxxxxxxxxxxxxxxxxxx> wrote: >> Mike Chan <mike@xxxxxxxxxxx> writes: >> >>> IO events can also come from GPIO modules, which reside in the PER domain. >>> It is possible for the PER to enter RET while CORE is still in ON. >>> If GPIO 2-6 are enabled for IO-pad wakeups, the PER domain will not >>> wakeup in this case, unless we enable it. >>> >>> Signed-off-by: Mike Chan <mike@xxxxxxxxxxx> >> >> Hi Mike, >> >> I'm a little puzzled on this one. My understanding is that the IO pad >> is only armed when CORE is in RET or OFF. >> > > The issue we are seeing is when the device is active but idle, if CORE > is ON and PER is in RET and the omap is sitting in swfi. If the user > presses a keypad button, IO pad doesn't wake us out of idle. Setting a > wakeup if PER or CORE goes into RET solve this. > >> I need to dig a little more in the TRM on this one to clarify. >> > > I was looking at 4.11.2.2 I/O Wake-Up Mechanism (pg 421) > Yeah, that's the right place. After a little more digging and asking around, this looks like a good fix, but there's a minor problem with the implementation: In the section of the TRM you referenced the following sentence is hiding: "Software must wait for the I/O daisy chain to complete before it transitions the PER domain to a nonfunctional state." In the proposed patch, it's likely that PER could transition to INACTIVE/RET/OFF before the IO wakeups are enabled. For example, if nothing in PER is active except UART3, then PER will transition to an idle state right after omap_uart_prepare_idle(2), which is before the IO wakeups are currently enabled. To be perfectly safe, the IO wakeups should be enabled before PER is allowed to transition. Kevin -- 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
