On Monday 26 February 2007 18:18, Alan wrote: > > Yeah, I need semaphore. This is a hw register that says when the hw > > is ready to accept a new command. Code that wants to send commands has > > to down the semaphore and then send it. When hw is ready to get a new > > command, it sends and IRQ and the IRQ up()s the semaphore. > > So you need a mutex not a semaphore
Theoretically I could use a mutex. Practically it would trigger ugly complications. Only the owner can unlock a mutex (for example), so I could not unlock from an IRQ handler -- not to mention that the semantic rules outlined in Documentation/mutex-design.txt explicitly forbid IRQ usage. And then, this is what semaphores where designed for, as gates :) for once that I get to use a semaphore properly... - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
