Re: [FFADO-devel] Segfault when watchdog object is deleted

[Clemens L. <cl...@la...>]

Jonathan Woithe wrote:
> On Fri, Jul 12, 2013 at 03:50:43PM +0200, Clemens Ladisch wrote:
>> Jonathan Woithe wrote:
>>> I'm working on a patch to fix this.  We can't just Stop() the PosixThreads
>>> because the sleep time can be quite lengthy.  Libffado would therefore take
>>> quite a few seconds to clean up typically, which is inconvenient.  I expect
>>> the solution to involve some combination of Stop() and pthread_signal()
>>
>> The 'proper' way to implement this is to send a message to the thread.
>> This is typically implemented with a pipe for the message and using
>> poll() for the sleep; if you need more than millisecond resolution, use
>> ppoll() or add a timerfd to the polled fds.
>
> [...]
> SystemTimeSource must use CLOCK_MONOTOMIC or CLOCK_MONOTOMIC_RAW to maintain
> consistent timing with the streaming sections of FFADO.  Is there a way to
> explicitly select the clock used by ppoll()?

The select/poll functions use CLOCK_MONOTONIC.

If you want to change this, don't use poll's built-in timeout but add
a timer created with timerfd_create.  (But neither clock_nanosleep nor
timerfd_create support CLOCK_MONOTONIC_RAW.)


Regards,
Clemens