Re: Atomic operators in alsa driver

[Takashi Iwai <tiwai@suse.de>]

At Wed, 11 Aug 2004 15:19:20 +0200 (CEST),
Jaroslav wrote:
> 
> On Tue, 10 Aug 2004, Eliot Blennerhassett wrote:
> 
> > A question to clarify which 'operators' are atomic i.e. inside spinlock.
> > 
> > As far as I can make out from Takashi's Writing an Alsa driver, Chapter 5,
> > section "Operators" (am I correct?)
> > 
> > Atomic:
> > trigger callback
> > pointer callback
> > 
> > Non-atomic:
> > open callback
> > close callback
> > ioctl callback
> > hw_params callback
> > hw_free callback
> > prepare callback
> > copy and silence callbacks
> > ack callback
> > page callback
> 
> It's correct.

In practice, ack callback is usually treated as atomic to get finer
processing of data transfer.  For example, ack is called in the
pointer callback in pcm-indirect.h.  But basically it can be
non-atomic, too.


Takashi


-------------------------------------------------------
SF.Net email is sponsored by Shop4tech.com-Lowest price on Blank Media
100pk Sonic DVD-R 4x for only $29 -100pk Sonic DVD+R for only $33
Save 50% off Retail on Ink & Toner - Free Shipping and Free Gift.
http://www.shop4tech.com/z/Inkjet_Cartridges/9_108_r285