HID: cp2112: fix to force single data-report reply

commit 6debce6f4e787a8eb4cec94e7afa85fb4f40db27 upstream.

Current implementation of cp2112_raw_event() only accepts one data report at a
time. If last received data report is not fully handled yet, a new incoming
data report will overwrite it. In such case we don't guaranteed to propagate
the correct incoming data.

The trivial fix implemented here forces a single report at a time by requesting
in cp2112_read() no more than 61 byte of data, which is the payload size of a
single data report.

Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Tested-by: Ellen Wang <ellen@cumulusnetworks.com>
Signed-off-by: Jiri Kosina <jkosina@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/hid/hid-cp2112.c b/drivers/hid/hid-cp2112.c
index 3318de6..a2dbbbe 100644 (file)
--- a/drivers/hid/hid-cp2112.c
+++ b/drivers/hid/hid-cp2112.c
@@ -356,6 +356,8 @@ static int cp2112_read(struct cp2112_device *dev, u8 *data, size_t size)
        struct cp2112_force_read_report report;
        int ret;
 
+       if (size > sizeof(dev->read_data))
+               size = sizeof(dev->read_data);
        report.report = CP2112_DATA_READ_FORCE_SEND;
        report.length = cpu_to_be16(size);