Re: [PATCH v2 1/1] HID: logitech: read all 32 bits of report typebitfield
From: Jonathan Nieder
Date: Fri May 11 2012 - 20:44:15 EST
Nestor Lopez Casado wrote:
> From: Jonathan Nieder <jrnieder@xxxxxxxxx>
> On big-endian systems (e.g., Apple PowerBook), trying to use a
> logitech wireless mouse with the Logitech Unifying Receiver does not
> work with v3.2 and later kernels. The device doesn't show up in
> /dev/input. Older kernels work fine.
> That is because the new hid-logitech-dj driver claims the device. The
> device arrival notification appears:
> 20 00 41 02 00 00 00 00 00 00 00 00 00 00 00
> and we read the report_types bitfield (02 00 00 00) to find out what
> kind of device it is. Unfortunately the driver only reads the first 8
> bits and treats that value as a 32-bit little-endian number, so on a
> powerpc the report type seems to be 0x02000000 and is not recognized.
Sigh, I took the wrong line in this example. The above event is
"device list empty" and report_types is 0 as you'd expect. The
example I meant to use:
20 01 41 01 1a 10 04 00 00 00 00 00 00 00 00
and we read the report_types bitfield (04 00 00 00) to find out what
kind of device it is. Unfortunately the driver only reads the first 8
bits and treats that value as a 32-bit little-endian number, so on a
powerpc the report type seems to be 0x04000000 and is not recognized.
Jiri, please amend the message if convenient, or I'm fine with leaving
it be if not. Sorry for the nonsense.
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/