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
Hi Erik,
On Thu, Apr 23, 2020 at 11:07 AM Erik Andresen <[email protected]> wrote:
>
> 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?
Afaik each report ID will need to have its own characteristic, at
least that is how HIDS has put the spec, but if I got you right the
report->id is never initialized on report_reference_cb so this might
be how Android is detecting if there is a report ID or not, we should
be able to confiirm this if we have access to the HCI trace when
discovering the services.
> greetings,
> Erik Andresen
--
Luiz Augusto von Dentz
Hi,
Am 27.04.20 um 19:18 schrieb Luiz Augusto von Dentz:
> Hi Erik,
>
> On Thu, Apr 23, 2020 at 11:07 AM Erik Andresen <[email protected]> wrote:
>>
>> 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?
>
> Afaik each report ID will need to have its own characteristic, at
> least that is how HIDS has put the spec, but if I got you right the
> report->id is never initialized on report_reference_cb so this might
> be how Android is detecting if there is a report ID or not, we should
> be able to confiirm this if we have access to the HCI trace when
> discovering the services.
thanks for taking a look. I have attached the saved btsnoop from btmon, it contains the full pairing process from scan to connecting. I hope this is what you wanted, if not please let me know. The device in question is the "EB:47:34:30:3F:3E".
greetings,
Erik Andresen