On Sat, 17 Oct 2009, Daniel Mack wrote:
On Mon, Sep 28, 2009 at 10:33:35AM +0200, Takashi Iwai wrote:
At Sat, 26 Sep 2009 17:06:23 +0100 (BST), Mark Hills wrote:
On Fri, 25 Sep 2009, Daniel Mack wrote:
On Fri, Sep 25, 2009 at 04:22:15PM +0100, Mark Hills wrote:
The driver documentation states that local interrupts are already disabled when trigger() is called, so only a spinlock is required.
Hmm. I assume you tested them well. But I remember to have had quite some trouble at this point on SMP machines and ended up with that irqsave code. However, if you're sure that fixes a bug or is not necessary, let's take the patches and I'll test them once I'm back home around mid Oct.
I did check both non and SMP machines, and it corresponds to the docs. I also removed the patches to verify I could reproduce the original problems.
The irqsave is needed for deactivate_substream() because it's called also in your hw_free callback, which is non-atomic. In the real case, it's hard to hit this codepath, though.
Well, the nature of race conditions is that they are hard to hit, right? ;)
However, I tested the patches now, and couldn't reproduce anything like the things I remember I had.
So from my side, they can go in then. Sorry for the long delay on this.
No, Takashi is correct -- deactivate_substream() is also used in hw_free. It means that "[PATCH 1/4] Do not disable local interrupts" should not be applied. It was meant to be a cleanup only but introduces a new problem.
The other patches (2-4) are good and should be applied. I'll resubmit with my Signed-off-by, but this will be in a week or so.