I have a device that has the following hid report descriptor:
---------------------
...
Collection (Logical) A1 02
Usage Page (Physical Input Device) 05
Usage (DC Enable Actuators) 09 97
Logical Minimum (0) 15 00
Logical Maximum (1) 25 01
Report Size (4) 75 04
Report Count (1) 95 01
Output (Data,Var,Abs,NWrp,Lin,Pref,NNul,NVol,Bit) 91 02
Logical Minimum (0) 15 00
Logical Maximum (0) 25 00
Output (Cnst,Var,Abs,NWrp,Lin,Pref,NNul,NVol,Bit) 91 03
Usage (Magnitude) 09 70
Logical Minimum (0) 15 00
Logical Maximum (100) 25 64
Report Size (8) 75 08
Report Count (4) 95 04
Output (Data,Var,Abs,NWrp,Lin,Pref,NNul,NVol,Bit) 91 02
...
End Collection C0
---------------------
I would therefore expect that the device wants data in the following manner:
8 Bits: Report ID, 4 Bits: DC Enable Actuators, 4 Bits: Padding, 32
Bits: Magnitude
Hence, my driver code in linux would look something like that:
---------------------
...
static const u8 buf[] = {0x03, 0b00010000, 0x00, 0x00, 0x60, 0x60, 10,
0x00, 10};
hid_hw_output_report(hid, buf, 9);
...
---------------------
Unfortunately that's not what the device expects! In fact it does only
react if the data is structured like:
8 Bits: Report ID, 4 Bits: Padding, 4 Bits: DC Enable Actuators, 32
Bits: Magnitude
Which is:
---------------------
...
static const u8 buf[] = {0x03, 0b00000001, 0x00, 0x00, 0x60, 0x60, 10,
0x00, 10};
hid_hw_output_report(hid, buf, 9);
...
---------------------
That means the padding comes before the DC Enable Actuators field, not
after.
Does anyone understand why these two fields are switched? Is there
something i am missing?
Thank you in advance!
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