[PW_SID:951281] [BlueZ,1/3] shared/io: add watcher to be used with TX timestamping

[BluezTestBot]

Add special implementation of fd watcher GSource for audio use.

For audio use cases, sound server may turn on TX timestamping on a
socket that we are watching. In this case, we shall not consider the TX
timestamping POLLERR as a socket error condition, nor read the TX
timestamps.

When TX timestamps appear in errqueue, switch from fd poll wait to
polling the fd at regular intervals. This is because unread errqueue
causes poll() to wake up immediately, so the mainloop cannot block on
that, and we have to use a timer instead with some reasonable timeout
for the use case.

This rate limits wakeups on new TX timestamps we aren't going to read,
and also avoids the busy looping if timestamping was left on but
errqueue is not flushed.

Kernel does not provide any way for user applications to disable wakeup
on POLLERR currently. Note that even with epoll() POLLET it still wakes
up on every timestamp.

Implement this only for io-glib; it is only needed for audio use cases
that anyway are using glib, so add a glib-specific API for it in
addition to the 'struct io *' one. Uses features from GLib 2.36 (from
2013) so update configure.ac also.

Notes:
v2:
- Remove io-glib.h. Pass void * for GIOChannel *, which is how
it needs to be if it's in io.h as requested.
- Adjust API a bit

In theory avdtp/bap could be changed to use a 'struct io *' instead, but
it's mostly additional complication with no gain since they are using
GLib anyway, and in theory 'struct io *' users shall use the
io_set_ignore_errqueue API instead.

acinclude.m4 | 4 +-
configure.ac | 2 +-
src/shared/io-ell.c | 12 +++
src/shared/io-glib.c | 185 ++++++++++++++++++++++++++++++++++++++-
src/shared/io-mainloop.c | 12 +++
src/shared/io.h | 5 ++
6 files changed, 216 insertions(+), 4 deletions(-)

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CheckPatch
Desc: Run checkpatch.pl script
Duration: 0.25 seconds
Result: PENDING

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GitLint
Desc: Run gitlint
Duration: 0.23 seconds
Result: PENDING

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BuildEll
Desc: Build and Install ELL
Duration: 21.00 seconds
Result: PASS

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BluezMake
Desc: Build BlueZ
Duration: 2613.93 seconds
Result: PASS

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MakeCheck
Desc: Run Bluez Make Check
Duration: 19.83 seconds
Result: PASS

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MakeDistcheck
Desc: Run Bluez Make Distcheck
Duration: 198.31 seconds
Result: PASS

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CheckValgrind
Desc: Run Bluez Make Check with Valgrind
Duration: 274.35 seconds
Result: PASS

[BluezTestBot]

CheckSmatch
Desc: Run smatch tool with source
Duration: 302.66 seconds
Result: WARNING
Output:

src/shared/bap.c:314:25: warning: array of flexible structuressrc/shared/bap.c: note: in included file:./src/shared/ascs.h:88:25: warning: array of flexible structuressrc/shared/bap.c:314:25: warning: array of flexible structuressrc/shared/bap.c: note: in included file:./src/shared/ascs.h:88:25: warning: array of flexible structuressrc/shared/bap.c:314:25: warning: array of flexible structuressrc/shared/bap.c: note: in included file:./src/shared/ascs.h:88:25: warning: array of flexible structures

[BluezTestBot]

bluezmakeextell
Desc: Build Bluez with External ELL
Duration: 128.49 seconds
Result: PASS

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IncrementalBuild
Desc: Incremental build with the patches in the series
Duration: 0.25 seconds
Result: PENDING

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ScanBuild
Desc: Run Scan Build
Duration: 897.96 seconds
Result: PASS