Re: [PATCH] HID: cp2112: fix to force single data-report reply

From: Ellen Wang
Date: Wed Jul 01 2015 - 04:05:43 EST


Works as described. Thank you!

By the way, I tested the code with and without your fix on my rev 2 chip, and it behaved the same way as you describe on your rev 1 chip.

On 06/20/2015 11:20 PM, Antonio Borneo wrote:
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@xxxxxxxxx>
---

Hi Jiri,

I think this should go through linux-stable.

Thanks,
Antonio

drivers/hid/hid-cp2112.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/hid/hid-cp2112.c b/drivers/hid/hid-cp2112.c
index 3318de6..a2dbbbe 100644
--- 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);


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