Eliminate the dependency on the non-portable bt_put_le16() routine. It
isn't available in all supported BlueZ versions, and won't be available
in other platform backends. Prefer write_u16le() which is available on
all sigrok supported platforms.
There are cases where the connect() call returns EBUSY when trying to
connect to a device. This has been observed when sampling an RDTech
UM24C. In this case, scanning the device works fine. However, when
sampling the device, Sigrok first scans the device, then closes the
connection and re-opens it to sample the device. If the close/open
calls happen in close successions, the Bluetooth stack sometimes
returns EBUSY.
Work around this issue by retrying if the connect() returns EBUSY.
Signed-off-by: Andreas Sandberg <andreas@sandberg.pp.se>
Even working BLE devices won't immediately succeed in the first call to
connect(2), which is why the "in progress" phase was added. But absent
peers made the previous implementation try forever, getting stuck in the
sr_bt_connect_ble() call.
Try to balance these two constraints. Do terminate BLE connect attempts
after a generous timeout. When this 20s period passed, there probably is
a configuration error or unresponsive peer. Yet the timeout needs to be
in this ballpark to not erroneously fail for working setups.
Create a src/bt/ subdirectory for source files. Declare a platform
agnostic internal API for Bluetooth communication, and provide an
implementation of that portable API when the BlueZ library is available.
This implementation assumes that HAVE_BLUETOOTH and HAVE_LIBBLUEZ can be
used interchangeably, which is true for this initial version. When
support for other platforms gets added, the common and the specific
parts need to get sorted. Trying that now would involve guessing. :)
Gerhard Sittig
Andreas Sandberg
Uwe Hermann