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| author | Jonathan Nieder <jrnieder@gmail.com> | 2012-05-11 16:17:16 +0200 |
|---|---|---|
| committer | Jiri Kosina <jkosina@suse.cz> | 2012-05-11 16:31:21 +0200 |
| commit | 44d27f7dfedd9aadc082cda31462f6600f56e4ec (patch) | |
| tree | 66935ad1e6ed841e83e4adbb031a93bbc0cbf5b3 /drivers/hid/hid-logitech-dj.c | |
| parent | 74b89e8a3625c17c7452532dfb997ac4f1a38751 (diff) | |
| download | lwn-44d27f7dfedd9aadc082cda31462f6600f56e4ec.tar.gz lwn-44d27f7dfedd9aadc082cda31462f6600f56e4ec.zip | |
HID: logitech: read all 32 bits of report type bitfield
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>
Diffstat (limited to 'drivers/hid/hid-logitech-dj.c')
| -rw-r--r-- | drivers/hid/hid-logitech-dj.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/hid/hid-logitech-dj.c b/drivers/hid/hid-logitech-dj.c index 2b56efcbdf61..d44ea58c597e 100644 --- a/drivers/hid/hid-logitech-dj.c +++ b/drivers/hid/hid-logitech-dj.c @@ -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; |