Previously, invalid ringbuffer pointers were always handled during the
second pass. But that changed after the previous commit. If the invalid
pointer is located in the first logbook entry, this is now handled as
"no dives present". Fixed by returning the correct error code instead.
If all the entries in the logbook ringbuffer happen to be empty, the
ringbuffer end pointer will not have a valid value. Creating the
ringbuffer stream will fail, and an error will be returned to the
caller. Fixed by adding an extra check, and exit if there are no dives.
The depth value is encoded with only 11 bits instead of 12 bits. The
extra bit contains the gas mix index. This resulted in wrong depths,
with values larger than 204.8m.
For the BCD encoded day field (range 1-31), two bits are sufficient to
represent the upper digit (range 0-3). The purpose of the highest bit is
unknown, but it's certainly not part of the day field, and needs to be
masked off.
The bluetooth device filtering is based on the fact that the format of
the bluetooth device name is something like 'FQ001124', where the two
first letters are the ASCII representation of the model number (e.g.
'FQ' or 0x4651 for the i770R), and the six digits are the serial number.
It seems that the BLE communication protocol is somewhat different from
the serial one in the version string: while the serial version tends to
show the memory size, the BLE version string has some other numeric
pattern.
Linus Torvalds reports the BLE pattern for the i770R is normally just
"0001", allthough he once also observed "0090" with the same dive
computer. A communication trace from a Pro Plus X also showed "0001".
We don't have enough information to guess the meaning of the number.
Regardless, for those two dive computers supporting BLE, make the
pattern simply ignore the last four digits, since they clearly vary.
Based-on-code-by: Linus Torvalds <torvalds@linux-foundation.org>
The BLE communication sends a handshake packet containing a passphrase
based on the serial number of the device. Sadly, we can't actually read
the serial number from the device until after this handshake has
successfully completed, which makes it a bit of a chicken-and-egg
problem from a communication standpoint. However, the serial number is
also exposed in the bluetooth device name the device advertizes, which
is the reason for the newly added DC_IOCTL_BLE_GET_NAME ioctl.
Thanks to Janice McLaughlin for pointing out the logic of this magic
handshake.
Based-on-code-by: Linus Torvalds <torvalds@linux-foundation.org>
Refactor the packet receiving code to read the ack byte, the payload
data and the checksum all at once, with just a single read operation.
This is not only a bit more efficient, but will also simplify the BLE
support.
The trailing zero byte is present for historic reasons only. At the time
the Oceanic protocol was implemented, the Oceanic application send this
extra zero byte too, and we simply copied this behaviour. But more
recent versions no longer send it. Probably a small (harmless) bug that
was fixed.
The write command is send as two separate packets. The first packet
contains the B2 command and the page number, and the second packet
contains the payload and checksum. Because the payload can contain
arbitrary data, the first byte of a packet is not necessary a command
byte. But the code to select the correct ack byte is based on this
assumption. Fixed by passing the expected ack byte.
The set_latency function is the perfect example of a feature that should
be implemented as an ioctl: it's only implemented by a single driver,
and the functionality is also highly platform specific.
This new ioctl function allows to perform I/O stream specific requests
through a generic interface. This provides an easy way to extend the I/O
interface with some driver specific features, without having to modify
the public api.
Replace the manual polling, implemented using a combination of the
dc_iostream_get_available and dc_iostream_sleep functions, with the new
and more efficient poll function.
The Linux implementation is very straighforward and just a lightweight
wrapper around the select function. But the Windows implementation is
much more complex, because the Windows event notification mechanism
behaves very different:
The WaitCommEvent function does not support a timeout and is always a
blocking call. The only way to implement a timeout is to use
asynchronous I/O (or overlapped I/O as it's called in the Windows API),
to run the operation in the background. This requires some additional
book keeping to keep track of the pending background operation.
The event mechanism is also edge triggered instead of level triggered,
and reading the event with the WaitCommEvent function clears the pending
event. Therefore, the state of the input buffer needs to be checked with
the ClearCommError function before and after the WaitCommEvent call.
The check before is necessary in case the event is already cleared by a
previous WaitCommEvent call, while there is still data present in the
input buffer. In this case, WaitCommEvent should not be called at all,
because it would wait until more data arrives.
The check afterwards is necessary in case WaitCommEvent reports a
pending event, while the data in the input buffer has already been
consumed. In this case, the current event must be ignored and
WaitCommEvent needs to be called again, to wait for the next event.
The BLE communication is significant slower than usb-serial. The first
BLE data packet of each response often takes longer than one second to
arrive. This causes the first attempt to fail with a timeout. The second
attempt will appear to succeed, because it actually receives the
response of the first attempt. But now the next command will fail,
because it will receive the response of the second attempt of the
previous command.
Increasing the timeout and adding an extra delay before retrying, avoids
this problem.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
For the Aeris Manta, the end of the profile ringbuffer appears to depend
on the firmware version. For older firmware versions (1x), the end of
the ringbuffer is at address 0xFFF0, while for the newer versions (2x),
it's 0xFE00.
The code checks for firmware version 2B, because that's the lowest known
version in the 2x range.
Reported-by: Nick Shore <support@mac-dive.com>
The logbook ringbuffer is always updated sequentially. Therefore, emtpy
entries can only be present after the oldest dive. However it appears
that under some special conditions (for example an empty battery during
the dive), the logbook entry is not always stored correctly, which can
result in an empty entry after all.
I suspect that at the start of each dive, the OSTC erases the next
available entry in the logbook ringbuffer and updates the internal write
pointer. Once the dive is finished, the actual content of the erased
logbook is written. Thus, when the OSTC runs out of battery power during
the dive, that last step never happens, and the erased entry remains in
place.
As a workaround, ignore all empty logbook entries instead of assuming we
reached the last dive.
Due to a bug in the hwOS Tech firmware v3.03 to v3.07, and the hwOS
Sport firmware v10.57 to v10.63, the ppO2 divisor is sometimes not
correctly reset to zero when no ppO2 samples are being recorded.
Usually this condition can be detected by the fact that the length of
the extended sample will not have enough space left for the ppO2 sample
(9 bytes). As a workaround, reset the divisor back to zero to manually
disable the ppO2 samples.
In theory this detection method is not 100% reliable. There can still be
other sample types present in the extended sample. If their total size
is larger than 9 bytes, the bug will not be detected at all. Instead,
those bytes will get interpreted as the ppO2 sample, resulting in bogus
ppO2 values. Additionally, one of the other sample types will now run
out of space and cause the parsing to fail with an error. However, in
practice this risk is relative low. Most of the other samples are
relative small (1 or 2 bytes), so you would need many of them. That's
rather unlikely in most configurations. The only exception is the large
deco plan sample (15 bytes).
In commit 2829f7ebf9902170bf653d67dbe412a0a4f140cf, the hwos parameter
of the hw_ostc_parser_create() function was kept to preserve backwards
compatibility. Since the function has been removed from the public api,
the parameter can be removed now.
The workaround for the tank pressure in the previous commit is only
relevant for the newer hwOS based devices, and not for the original OSTC
devices. In practice this doesn't cause any problems because the
original OSTC doesn't support a tank pressure sensor, but nevertheless
it's better to use the correct condition.
The tank pressure is stored with a resolution of 1 bar instead of 0.1
bar. There is however one exception. The hwOS Sport firmware used a
resolution of 0.1 bar between versions 10.40 and 10.50.
Unfortunately the only way to distinguish the Sport from the Tech
variant is the different range of the version number (10.x vs 3.x). The
consequence is that this workaround will start to produce wrong results
once the firmware version number of the hwOS tech variant reaches the
10.x range. If that ever happens, this workaround should be removed
again!
Some of the newer Shearwater dive computers support up to 2 tank
pressure sensors. The tank pressure samples were already reported, but
the tank field with the corresponding begin/end pressure was still
missing.
To be able to collect the tank begin/end pressure, the log version needs
to be available earlier, because it's needed for parsing the tank
pressure data in the samples. Therefore, extract the log version
immediately after locating the opening record.
Add the Shearwater Nerd 2 bluetooth device name.
The change to uppercase is purely cosmetic. The string comparisions are
not case-sensitive. But for documentation purposes it's good practice to
list the exact name as reported by the device.
