../dbus/reserve.c:154:16: warning: implicit truncation from 'int' to a one-bit wide bit-field changes value from 1 to -1 [-Wsingle-bit-bitfield-constant-conversion]
154 | d->gave_up = 1;
| ^ ~
siginfo is disabled by default so building on new CPU
architectures does not require adjusting of siginfo.c anymore.
When needed, --siginfo can be used as option to ./waf configure
to enable the functionality
Backup repo: https://github.com/LADI/jack_control
dbus/jack_control is now submodule
jack_control is now always installed as part of jackdbus.
With dedicated repos for jackdbus and jack_control,
there is no point in having jack_control installation conditional.
show command behaves a bit like last parts of (current) adevices.sh script,
but chains the involved commands status2, dg, dp and ep internally.
The adevices.sh script uses status command and does not display
JACK settings unless jack is started. The show command uses
status2, so the settings will be displayed always.
This commit changes build info to display info about jackdbus itself,
along with libjackserver.so provided build info
Fixes https://github.com/LADI/jackdbus/issues/1
* fix ringbuffer thread safety on ARM. fix#715#388
This patch addresses the thread safety problem of `jack_ringbuffer_t`
mentioned in #715 and #388. The overbound read bug caused by this problem
is impossible to reproduce on x86 due to its strong memory ordering, but
it is a problem on ARM and other weakly ordered architectures.
Basically, the main problem is that, on a weakly ordered architecture,
it is possible that the pointer increment after `memcpy` becomes visible
to the other thread before `memcpy` finishes:
memcpy (&(rb->buf[rb->write_ptr]), src, n1);
// vvv can be visible to reading thread before memcpy finishes
rb->write_ptr = (rb->write_ptr + n1) & rb->size_mask;
If this happens, the other thread can read the remaining garbage values
in `rb->buf` due to be overwritten by the unfinished `memcpy`.
To fix this, an explicit pair of release/acquire memory fences [1] is
used to ensure the copy on the other thread *happens after* the `memcpy`
finishes so no garbage values can be read.
[1]: https://preshing.com/20130922/acquire-and-release-fences/
* remove volatile qualifier on ringbuf r/w pointers
The volatile constraints are excess when compiler barriers are present.
It generates unnecessary `mov` instructions when pointers aren't going
to be updated.
* simplify read/write space calculations
This optimization is possible because the buffer size is always a power
of 2. See [1] for details.
[1]: https://github.com/drobilla/zix/pull/1#issuecomment-1212687196
* move acq fences to separate lines
falkTX
Christian Clauss
luz paz
Daan De Meyer
K
Florian Walpen