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

borneoa · Jiri Kosina · commit 6debce6f4e78 · 2015-07-08T12:40:23.000+02:00
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.

Cc: stable@vger.kernel.org
Signed-off-by: Antonio Borneo &lt;borneo.antonio@gmail.com&gt;
Tested-by: Ellen Wang &lt;ellen@cumulusnetworks.com&gt;
Signed-off-by: Jiri Kosina &lt;jkosina@suse.com&gt;
diff --git 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);
 
