[linux-dvb] [BUG] flexcop lockdep

Antti Seppälä ajhseppa at niksula.hut.fi
Thu Apr 5 21:57:26 CEST 2007

Patrick Boettcher wrote:
> On Thu, 5 Apr 2007, Borgi2008 wrote:
>> Am Mittwoch, den 04.04.2007, 23:29 +0300 schrieb Antti Seppälä:
>>> Borgi2008 wrote:
>>>> Hello,
>>>> i've created a bugfixes. Hope it could helps you.
>>>> Hendrik Borghorst
>>> Actually, looking at the code I cannot figure out why there has to be a
>>> spinlock in the first place.
>>> The lock is only taken in the interrupt handler which already runs in
>>> atomic context so there is no use in making the handler protected by a
>>> spinlock. Am I missing something here?
>>> I think the spinlock is unnecessary and should be removed entirely.
> Even on SMP systems? ISRs are only atomic on one CPU.
> Patrick.

Apparently I've used to thinking too much in the UP world.

It seems that flexcop interrupts are not acked with a special register
write so an interrupt can then occur even while it is being processed on
another CPU.(?)

In that case the patch from Hendrik is correct.

Antti Seppälä

More information about the linux-dvb mailing list