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HID: logitech: read all 32 bits of report type bitfield

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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.

Even on little-endian machines, connecting a media center remote
control (report type 00 01 00 00) with this driver loaded would
presumably fail for the same reason.

Fix both problems by using get_unaligned_le32() to read all four
bytes, which is a little clearer anyway.  After this change, the
wireless mouse works on Hugo's PowerBook again.

Based on a patch by Nestor Lopez Casado.
Addresses http://bugs.debian.org/671292

Reported-by: Hugo Osvaldo Barrera <hugo@osvaldobarrera.com.ar>
Inspired-by: Nestor Lopez Casado <nlopezcasad@logitech.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Nestor Lopez Casado <nlopezcasad@logitech.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This commit is contained in:
Jonathan Nieder 2012-05-11 16:17:16 +02:00 committed by Jiri Kosina
parent 74b89e8a36
commit 44d27f7dfe
1 changed files with 3 additions and 2 deletions
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5
drivers/hid/hid-logitech-dj.c
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@ -26,6 +26,7 @@
#include <linux/hid.h>
#include <linux/module.h>
#include <linux/usb.h>
#include <asm/unaligned.h>
#include "usbhid/usbhid.h"
#include "hid-ids.h"
#include "hid-logitech-dj.h"
@ -265,8 +266,8 @@ static void logi_dj_recv_add_djhid_device(struct dj_receiver_dev *djrcv_dev,
goto dj_device_allocate_fail;
}
dj_dev->reports_supported = le32_to_cpu(
dj_report->report_params[DEVICE_PAIRED_RF_REPORT_TYPE]);
dj_dev->reports_supported = get_unaligned_le32(
dj_report->report_params + DEVICE_PAIRED_RF_REPORT_TYPE);
dj_dev->hdev = dj_hiddev;
dj_dev->dj_receiver_dev = djrcv_dev;
dj_dev->device_index = dj_report->device_index;