MIME-Version: 1.0
From:   Jeremy Slemp <slempjeremy68@gmail.com>
Date:   Sun, 19 Dec 2021 14:41:49 -0800
Message-ID: <CAHtsx2rK9SE5fn=1hnEZ_GZV6EPVvFLM-O+0HPAk+h+LvsxL2w@mail.gmail.com>
Subject: Trouble parsing HID reports from PDP PS4 remote
To:     linux-bluetooth@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

I bought a PDP Bluetooth PS4 remote[0] in the hopes of using it to
send keypress events to my Python script via evdev[1].  I found that
some of the buttons on the remote generate HID events that are seen by
evdev, but others do not.  So I'd like to figure out the best way to
receive events from the currently-unsupported buttons.

bluetoothctl describes the device as:

Device 3E:09:EC:xx:xx:xx (public)
Name: PDP Media Remote
Alias: PDP Media Remote
Class: 0x0000250c
Paired: yes
Trusted: yes
Blocked: no
Connected: yes
LegacyPairing: no
UUID: Human Interface Device... (00001124-0000-1000-8000-00805f9b34fb)
UUID: PnP Information           (00001200-0000-1000-8000-00805f9b34fb)

The main module inside the device is an BTM0612C2P[2].


The "good" buttons flip a bit in a mask in bytes 2-5:

SHARE button, press/release:

> ACL Data RX: Handle 11 flags 0x02 dlen 15                           #2232 [hci0] 4474.225390
      Channel: 65 len 11 [PSM 19 mode 0] {chan 1}
        a1 01 08 10 00 09 00 16 73 47 06                 ........sG.
> ACL Data RX: Handle 11 flags 0x02 dlen 15                           #2233 [hci0] 4474.355396
      Channel: 65 len 11 [PSM 19 mode 0] {chan 1}
        a1 01 08 00 00 09 00 89 24 5e 56                 ........$^V

UP ARROW, press/release:

> ACL Data RX: Handle 11 flags 0x02 dlen 15                           #2240 [hci0] 4536.493867
      Channel: 65 len 11 [PSM 19 mode 0] {chan 1}
        a1 01 00 00 00 0a 00 8b 3c 03 4d                 ........<.M
> ACL Data RX: Handle 11 flags 0x02 dlen 15                           #2241 [hci0] 4536.727587
      Channel: 65 len 11 [PSM 19 mode 0] {chan 1}
        a1 01 08 00 00 0a 00 4a 77 73 7d                 .......Jws}

PINK SQUARE, press/release:

> ACL Data RX: Handle 11 flags 0x02 dlen 15                           #2259 [hci0] 4676.429686
      Channel: 65 len 11 [PSM 19 mode 0] {chan 1}
        a1 01 18 00 00 0a 00 c8 e0 93 1d                 ...........
> ACL Data RX: Handle 11 flags 0x02 dlen 15                           #2260 [hci0] 4676.639687
      Channel: 65 len 11 [PSM 19 mode 0] {chan 1}
        a1 01 08 00 00 0a 00 4a 77 73 7d                 .......Jws}


The "bad" buttons seem to transmit a constant in byte 6 instead of a
bitmask in bytes 2-5:

REWIND, press/release:

> ACL Data RX: Handle 11 flags 0x02 dlen 15                           #2261 [hci0] 4696.955007
      Channel: 65 len 11 [PSM 19 mode 0] {chan 1}
        a1 01 08 00 00 0a 17 8d f2 a0 fe                 ...........
> ACL Data RX: Handle 11 flags 0x02 dlen 15                           #2262 [hci0] 4697.163765
      Channel: 65 len 11 [PSM 19 mode 0] {chan 1}
        a1 01 08 00 00 0a 00 4a 77 73 7d                 .......Jws}

PLAY, press/release:

> ACL Data RX: Handle 11 flags 0x02 dlen 15                           #2264 [hci0] 4710.348944
      Channel: 65 len 11 [PSM 19 mode 0] {chan 1}
        a1 01 08 00 00 0a 16 1b c2 a7 89                 ...........
> ACL Data RX: Handle 11 flags 0x02 dlen 15                           #2265 [hci0] 4710.531446
      Channel: 65 len 11 [PSM 19 mode 0] {chan 1}
        a1 01 08 00 00 0a 00 4a 77 73 7d                 .......Jws}

PAUSE, press/release:

> ACL Data RX: Handle 11 flags 0x02 dlen 15                           #2266 [hci0] 4717.501552
      Channel: 65 len 11 [PSM 19 mode 0] {chan 1}
        a1 01 08 00 00 0a 1a 30 8e 11 80                 .......0...
> ACL Data RX: Handle 11 flags 0x02 dlen 15                           #2267 [hci0] 4717.685317
      Channel: 65 len 11 [PSM 19 mode 0] {chan 1}
        a1 01 08 00 00 0a 00 4a 77 73 7d                 .......Jws}

ENTER, press/release:

> ACL Data RX: Handle 11 flags 0x02 dlen 15                           #2293 [hci0] 4844.683443
      Channel: 65 len 11 [PSM 19 mode 0] {chan 1}
        a1 01 08 00 00 0a 0d f7 0b c2 03                 ...........
> ACL Data RX: Handle 11 flags 0x02 dlen 15                           #2294 [hci0] 4844.867210
      Channel: 65 len 11 [PSM 19 mode 0] {chan 1}
        a1 01 08 00 00 0a 00 4a 77 73 7d                 .......Jws}

I tried to decode these reports according to the USB HID spec but they
didn't make much sense to me beyond the "collection (application)"
part.  Can anyone help understand what this remote is doing?


[0] https://www.amazon.com/dp/B072C7YZFC
[1] https://python-evdev.readthedocs.io/en/latest/
[2] https://www.oemblue.com/download/BTM0612C2P%20Hardware%20Datasheet.pdf