The attached patch fixes the problems introduced in this commit:
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=eea0579fc85e64e9f05361d5aacf496fe7a151aa

- Fix nForce workaround by honouring the pointer_update var
- Revert "ns" to u64, as per the hrtimer API
- Revert to the zero-delay timer startup, since I can't reproduce any
  problem with it (please, give me the hint!)
Signed-off-by: NStas Sergeev <stsp@aknet.ru>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

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: NTakashi 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: NTakashi Iwai <tiwai@suse.de>

In order to be able to do range hrtimers we need to use accessor functions
to the "expire" member of the hrtimer struct.
This patch converts sound/ to these accessors.
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>

Change HRTIMER_CB_IRQSAFE to HRTIMER_CB_SOFTIRQ,
as suggested by Thomas Gleixner.
That solves the lock dependancy reported in
Bug #10701.
That also allows to call hrtimer_start()
directly, tasklet "stupid hack" removed.
Signed-off-by: NStas Sergeev <stsp@aknet.ru>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

It appears that alsa allows a sound buffer with size not
evenly devided by the period size. This triggers a warning in
snd-pcsp and floods the log. As a quick fix, the warning should
be disabled.
Signed-off-by: NStas Sergeev <stsp@aknet.ru>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

The attached patch adds back the compatibility code, allowing the
driver to work with older alsa-libs.
The removal was premature, it breaks the real-life configs.
Signed-off-by: NStas Sergeev <stsp@aknet.ru>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

pcsp: remove S16->U8 downsampling as dmix now supports U8 natively.
Signed-off-by: NStas Sergeev <stsp@aknet.ru>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

pcsp: locking fix.
Signed-off-by: NStas Sergeev <stsp@aknet.ru>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

- make pcsp_start_timer_tasklet static
- remove redundant includes. <asm/i8253.h> is not available on all platforms.
Signed-off-by: NStas Sergeev <stsp@aknet.ru>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>

Added PC-speaker sound driver (snd-pcsp).
Signed-off-by: NStas Sergeev <stsp@aknet.ru>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>