Kevin Hilman <khilman@xxxxxx> writes: [...] >> From: Paul Walmsley <paul@xxxxxxxxx> >> Date: Fri, 13 Jan 2012 02:10:30 -0700 >> Subject: [PATCH] ARM: OMAP3: PM: allow MPU to enter low-power states even >> when the UART is active >> >> For some reason, both the existing OMAP3 PM code and the OMAP3 CPUIdle >> driver prevent the MPU powerdomain from entering low-power modes when >> any UART isn't asleep. Possibly it is intended to minimize the ARM >> wakeup latency when UART activity arrives, but the UART has a FIFO >> that should handle this for most cases, with no dropped characters. I >> may be forgetting something important, though. And CORE/PER low-power >> states are a different matter entirely. > > Just FYI... the UART can_sleep hackery was removed for v3.3 and replaced > by using a PM QoS constraint: However, looking closer I see now that the constraint being used in the mailine driver uses the CPU_DMA_LATENCY QoS constraint, which is preventing deeper C states as well just like the current code (before your patch), so an similar fix will still be needed for mainline. 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
