On 03/04/2016 04:09 PM, Manuel Reimer wrote:
Hello,
I'm still doing my first steps with bluetooth on Linux...
I'm trying to get HID reports of a bluetooth game controller (PS4
gamepad). The relevant lines:
char dest[18] = "XX:XX:XX:XX:XX:XX";
int int_socket = socket(AF_BLUETOOTH, SOCK_SEQPACKET, BTPROTO_L2CAP);
struct sockaddr_l2 addr = { 0 };
addr.l2_family = AF_BLUETOOTH;
str2ba( dest, &addr.l2_bdaddr );
addr.l2_psm = htobs(L2CAP_PSM_HIDP_INTR);
connect(int_socket, (struct sockaddr *)&addr, sizeof(addr));
char buf[79] = { 0 };
int bytes_read;
bytes_read = recv(int_socket, buf, sizeof(buf), 0);
while(1) {
if( bytes_read > 0 ) {
printf("received [%s]\n", buf);
}
}
Yes, I do proper initialization and yes, my "real code" has error handling.
If I run this code for the first time (currently I have the "hidp"
module blacklisted to get sure I'm really the first user of the device),
then everything works as expected. Initialization is done and lines are
running through console.
Sometimes I'm able to Ctrl+C and restart *once* but it never is possible
to do a third try. If I do so, then the "read" just hangs forever. This
also happens if I disconnect the bluetooth device and reconnect it. I
have to "systemctl restart bluetooth" in this case to get a new chance.
What is happening here? For me it seems like the bluetooth daemon
"somehow" does some kind of "deadlocking". Maybe the controller keeps
sending and noone takes the messages which causes the daemon to deadlock?
How to get around this? Is it actually possible to get this stable? Is
there, for example, some command, I can send, so whatever hangs here is
reset?
Thank you for every answer...
Best regards,
Manuel
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I did a few more tries.
This is a "hcidump -x" of one connection from usermode. It sends out one
report (setting the LEDs on the controller) and successfully receives 10
HID reports. For whatever reason I don't see all 10 in the hcidump output...
http://pastebin.com/50g2nMWF
And this one is a dump of the "deadlocked" case:
http://pastebin.com/QKWp8E2G
In general both logs look much more "dirty" as a dump created with the
kernel module (hidp) attached...
Any help would be very welcome. Maybe someone can at least point me to a
different mailing list where someone may know how to do "stable usermode
bluetooth programming"?
Thank you very much in advance.
Best regards,
Manuel
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