Hi,
I have a simple bluetooth hid device which does work in Android but not with Linux 4.19/Bluez 5. It does have two collections in its hid description:
0xA1, 0x01, // Collection (Application)
0x85, 0x02, // Report ID (2)
(...)
0xC0, // End Collection
0xA1, 0x01, // Collection (Application)
0x85, 0x01, // Report ID (1)
(...)
0xC0, // End Collection
Complete description is attached.
Since there are multiple collections I understand that every report has to be prefixed with the id, so I send
[2,0,0,0x52,0,0,0,0,0] (9 bytes) for the keycode 0x52, ID is 2.
Output from btmon is:
ACL Data RX: Handle 3585 flags 0x02 dlen 16 #2072 [hci0] 485.047387
ATT: Handle Value Notification (0x1b) len 11
Handle: 0x0015
Data: 020000520000000000
This looks good for me so far, unfortunately Linux does not pick it up, in dmesg I get:
drivers/hid/hid-core.c: undefined report_id 0 received
cat /sys/kernel/debug/hid/0005:0000:0000.0003/events # gives me:
report (size 10) (numbered) = 00 02 00 00 52 00 00 00 00 00
so I get 10 bytes instead the 9 I send
So far I traced it to hog-lib.c, report_value_cb() of bluez where this extra 0 is prepended in the if (hog->has_report_id) block.
report->id is 0 at this point. If I skip this extra addition of the zero or manually set id=2 here it works as expected. Does someone has an idea what I do wrong or what I'm missing?
greetings,
Erik Andresen
0x05, 0x01, // Usage Page (Generic Desktop Ctrls)
0x09, 0x06, // Usage (Keyboard)
0xA1, 0x01, // Collection (Application)
0x85, 0x02, // Report ID (2)
0x05, 0x07, // Usage Page (Kbrd/Keypad)
0x19, 0xE0, // Usage Minimum (0xE0)
0x29, 0xE7, // Usage Maximum (0xE7)
0x15, 0x00, // Logical Minimum (0)
0x25, 0x01, // Logical Maximum (1)
0x75, 0x01, // Report Size (1)
0x95, 0x08, // Report Count (8)
0x81, 0x02, // Input (Data,Var,Abs,No Wrap,Linear,Preferred State,No Null Position)
0x95, 0x01, // Report Count (1)
0x75, 0x08, // Report Size (8)
0x81, 0x01, // Input (Const,Array,Abs,No Wrap,Linear,Preferred State,No Null Position)
0x95, 0x05, // Report Count (5)
0x75, 0x01, // Report Size (1)
0x05, 0x08, // Usage Page (LEDs)
0x19, 0x01, // Usage Minimum (Num Lock)
0x29, 0x05, // Usage Maximum (Kana)
0x91, 0x02, // Output (Data,Var,Abs,No Wrap,Linear,Preferred State,No Null Position,Non-volatile)
0x95, 0x01, // Report Count (1)
0x75, 0x03, // Report Size (3)
0x91, 0x01, // Output (Const,Array,Abs,No Wrap,Linear,Preferred State,No Null Position,Non-volatile)
0x95, 0x06, // Report Count (6)
0x75, 0x08, // Report Size (8)
0x15, 0x00, // Logical Minimum (0)
0x25, 0x73, // Logical Maximum (115)
0x05, 0x07, // Usage Page (Kbrd/Keypad)
0x19, 0x00, // Usage Minimum (0x00)
0x29, 0x73, // Usage Maximum (0x73)
0x81, 0x00, // Input (Data,Array,Abs,No Wrap,Linear,Preferred State,No Null Position)
0x09, 0x05, // Usage (0x05)
0x15, 0x00, // Logical Minimum (0)
0x26, 0xFF, 0x00, // Logical Maximum (255)
0x75, 0x08, // Report Size (8)
0x95, 0x02, // Report Count (2)
0xB1, 0x02, // Feature (Data,Var,Abs,No Wrap,Linear,Preferred State,No Null Position,Non-volatile)
0xC0, // End Collection
0x05, 0x0C, // Usage Page (Consumer)
0x09, 0x01, // Usage (Consumer Control)
0xA1, 0x01, // Collection (Application)
0x85, 0x01, // Report ID (1)
0x15, 0x00, // Logical Minimum (0)
0x25, 0x01, // Logical Maximum (1)
0x75, 0x01, // Report Size (1)
0x95, 0x01, // Report Count (1)
0x09, 0xB5, // Usage (Scan Next Track)
0x81, 0x02, // Input (Data,Var,Abs,No Wrap,Linear,Preferred State,No Null Position)
0x09, 0xB6, // Usage (Scan Previous Track)
0x81, 0x02, // Input (Data,Var,Abs,No Wrap,Linear,Preferred State,No Null Position)
0x09, 0xB7, // Usage (Stop)
0x81, 0x02, // Input (Data,Var,Abs,No Wrap,Linear,Preferred State,No Null Position)
0x09, 0xB8, // Usage (Eject)
0x81, 0x02, // Input (Data,Var,Abs,No Wrap,Linear,Preferred State,No Null Position)
0x09, 0xCD, // Usage (Play/Pause)
0x81, 0x02, // Input (Data,Var,Abs,No Wrap,Linear,Preferred State,No Null Position)
0x09, 0xE2, // Usage (Mute)
0x81, 0x02, // Input (Data,Var,Abs,No Wrap,Linear,Preferred State,No Null Position)
0x09, 0xE9, // Usage (Volume Increment)
0x81, 0x02, // Input (Data,Var,Abs,No Wrap,Linear,Preferred State,No Null Position)
0x09, 0xEA, // Usage (Volume Decrement)
0x81, 0x02, // Input (Data,Var,Abs,No Wrap,Linear,Preferred State,No Null Position)
0xC0, // End Collection
// 127 bytes
