On Thu, Feb 3, 2011 at 13:32, Greg KH wrote: > On Thu, Feb 03, 2011 at 01:29:08AM -0500, Mike Frysinger wrote: >> On Tue, Jan 11, 2011 at 00:16, Mike Frysinger wrote: >> > From: Sonic Zhang <sonic.zhang@xxxxxxxxxx> >> > >> > The RX lock is used to protect the RX buffer from concurrent access in DMA >> > mode between the timer and RX interrupt routines. ÂIt is independent from >> > the uart lock which is used to protect the TX buffer. ÂIt is possible for >> > a uart TX transfer to be started up from the RX interrupt handler if low >> > latency is enabled. ÂSo we need to split the locks to avoid deadlocking in >> > this situation. >> > >> > In PIO mode, the RX lock is not necessary because the handle_simple_irq >> > and handle_level_irq functions ensure driver interrupt handlers are called >> > once on one core. >> > >> > And now that the RX path has its own lock, the TX interrupt has nothing to >> > do with the RX path, so disabling it at the same time. >> >> ping ... > > Is this needed for .38? it fixes a possible deadlock that exists in current .38 rc, but i wouldnt call it a "critical" fix as it only affects certain edge cases. so if you want to merge for .38 or .39, either is OK for us i think. -mike -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
