Messages in this thread | | | Date | Fri, 14 Nov 2008 09:36:10 +0100 | From | Takashi Iwai <> | Subject | Re: mmotm 2008-11-13-17-22 uploaded (pc-speaker) |
| |
At Fri, 14 Nov 2008 09:30:01 +0100, Peter Zijlstra wrote: > > On Fri, 2008-11-14 at 09:17 +0100, Takashi Iwai wrote: > > At Fri, 14 Nov 2008 09:03:14 +0100, > > Peter Zijlstra wrote: > > > > > > On Fri, 2008-11-14 at 07:47 +0100, Takashi Iwai wrote: > > > > At Fri, 14 Nov 2008 07:36:54 +0100, > > > > I wrote: > > > > > > > > > > At Thu, 13 Nov 2008 21:18:42 -0800, > > > > > Randy Dunlap wrote: > > > > > > > > > > > > > > > > > > mmotm-2008-1113-1722/sound/drivers/pcsp/pcsp.c: In function 'snd_card_pcsp_probe': > > > > > > mmotm-2008-1113-1722/sound/drivers/pcsp/pcsp.c:99: error: 'HRTIMER_CB_IRQSAFE' undeclared (first use in this function) > > > > > > > > > > > > # CONFIG_SND_HRTIMER is not set > > > > > > > > > > snd-pcsp and CONFIG_SND_HRTIMER are independent. > > > > > The snd-pcsp driver code isn't changed over weeks, thus it must be the > > > > > change in hrtimer side. > > > > > > > > It's turned out to be the recent commint in the upstream: > > > > > > > > commit 621a0d5207c18012cb39932f2d9830a11a6cb03d > > > > Author: Peter Zijlstra <a.p.zijlstra@chello.nl> > > > > Date: Wed Nov 12 09:36:35 2008 +0100 > > > > > > > > hrtimer: clean up unused callback modes > > > > > > > > Impact: cleanup > > > > > > > > git grep HRTIMER_CB_IRQSAFE revealed half the callback modes are actually > > > > unused. > > > > > > > > Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> > > > > Signed-off-by: Ingo Molnar <mingo@elte.hu> > > > > > > > > This hits on snd-pcsp driver on linux-next, since it was switched to > > > > use this dropped flag. Now we get a build error. > > > > > > > > Can this commit be reverted? > > > > > > I think we determined the silly pc speaker driver should be using the > > > SOFTIRQ timer, why was this changed back again? > > > > It uses a tasklet inside now. > > The background story is: pcsp driver does register bit flips at each > > hrtimer callback. This should be done as accurate as possible for the > > sound quality (heh, who matters?). The register flip itself doesn't > > take time and no lock problem. Thus, IRQSAFE is more appropriate just > > for this task. > > > > The reason we used the softirq mode is the call of the ALSA core > > update part. This is eventually called after the given samples have > > been processed. And, this could cause a spin deadlock if called > > directly from hrtimer callback. > > > > In the latest code, the call of ALSA PCM core is off-loaded via > > tasklet for avoiding both spin deadlock and too long hrtimer > > handling. > > Aside from the fact that I think tasklets should die a horrible death > too,
Oh, if you'll kill them, please provide something compatible...
> could you, for now, try to use HRTIMER_CB_IRQSAFE_UNLOCKED ?
OK, I'll check it later.
thanks,
Takashi
| |