On Fri, 2006-12-08 at 21:15 +0100, Arnd Bergmann wrote: > On Friday 08 December 2006 21:05, Wolfgang Grandegger wrote: > > Can anybody tell me why the spin_* protection is needed? I thought that > > 32-bit read and write operations are atomic. > > > The spinlocks are needed to guarantee ordering between the completion of > the i/o access and other code. A typical problem is that a store is > still on its way to the I/O device while the CPU has already left the > function that initiated it, and might call code that relies on the > value having arrived there.
That will not help much with the spinlock, especially not seeing how they are used in the code. I think the lock is totally spurrious in that case. Ben. _______________________________________________ Linuxppc-embedded mailing list [email protected] https://ozlabs.org/mailman/listinfo/linuxppc-embedded
