On Thu, Feb 03, 2011 at 04:56:30PM -0500, Mike Frysinger wrote: > 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. It is independent from > >> > the uart lock which is used to protect the TX buffer. It is possible for > >> > a uart TX transfer to be started up from the RX interrupt handler if low > >> > latency is enabled. So 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. I can do it for .38, just wanted to check. I'll go queue it up now. thanks, greg k-h -- 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
