PIT_TICK_RATE is currently defined in four architectures, but in three
different places. While linux/timex.h is not the perfect place for it, it
is still a reasonable replacement for those drivers that traditionally use
asm/timex.h to get CLOCK_TICK_RATE and expect it to be the PIT frequency.
Note that for Alpha, the actual value changed from 1193182UL to 1193180UL.
This is unlikely to make a difference, and probably can only improve
accuracy. There was a discussion on the correct value of CLOCK_TICK_RATE
a few years ago, after which every existing instance was getting changed
to 1193182. According to the specification, it should be
1193181.818181...
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Len Brown <lenb@kernel.org>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Dmitry Torokhov <dtor@mail.ru>
Cc: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With the callback mode HRTIMER_CB_IRQSAFE_UNLOCK, the start of the
stream with zero delay doesn't work. Since IRQSAFE mode is removed,
we have to change the pcsp start-up code.
This patch splits the callback function to two parts, the triggering
of the port and the calculation of the expire time, and the update of
the ALSA PCM core. The first part is called both from the trigger-start
and the hrtimer callback while the latter is handled only in the
hrtimer callback.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
snd-pcsp driver takes chip->substream_lock together with PCM substream
lock. These are even mixed up with hrtimer's lock, resulting in messy
lock depencies. Right now, snd-pcsp driver resolves the deadlock by
using HRTIMER_CB_SOFTIRQ. However, this isn't nice for a really fast
path like bit-flipping.
This patch introduces a tasklet for PCM period handling so that the
hrtimer callback can be handled fast. This also reduce the use of
chip->substream_lock to avoid deadlocks. It's still used in pointer
callback, but even this could be removed with a proper barrier.
Another good solution is to introduce async trigger callback. But,
this will involve with a major rewrite of the PCM core code, so I
take first this easy fix.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This solves the problem with mixers wrongly displaying the PWM freq.
Signed-off-by: Stas Sergeev <stsp@aknet.ru>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
