Hello.
On 10/16/2015 1:07 AM, Konstantin Shkolnyy wrote:
Occasionally, writing data and immediately closing the port makes cp2108
stop responding. The device had to be unplugged to clear the error.
The failure is induced by shutting down the device while its Tx queue still has
unsent data. Reporting the correct amount of those data avoids the problem.
Adding tx_empty() has no adverse effect on other cp210x devices.
Signed-off-by: Konstantin Shkolnyy <konstantin.shkolnyy@xxxxxxxxx>
---
drivers/usb/serial/cp210x.c | 30 ++++++++++++++++++++++++++++++
1 file changed, 30 insertions(+)
diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index eac7cca..0189e64 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
[...]
@@ -249,6 +251,16 @@ static struct usb_serial_driver * const serial_drivers[] = {
#define CP210X_GET_CHARS 0x0E
#define CP210X_GET_PROPS 0x0F
#define CP210X_GET_COMM_STATUS 0x10
+/* Data returned by CP210X_GET_COMM_STATUS -- h/w doc says it's 0x13 bytes */
+struct cp210x_comm_status {
+ u32 errors;
+ u32 hold_reasons;
+ u32 amount_in_in_queue;
+ u32 amount_in_out_queue;
+ u8 eof_received;
+ u8 wait_for_immediate;
+ u8 reserved;
+};
Please don't declare structures amidst of the command #define's.
#define CP210X_RESET 0x11
#define CP210X_PURGE 0x12
#define CP210X_SET_FLOW 0x13
@@ -479,6 +491,24 @@ static void cp210x_close(struct usb_serial_port *port)
cp210x_set_config_single(port, CP210X_IFC_ENABLE, UART_DISABLE);
}
+static bool cp210x_tx_empty(struct usb_serial_port *port)
+{
+ int err;
+
Empty line hardly needed here.
+ /* get_config needs "array of integers large enough", so pad to 0x14 bytes */
+ struct cp210x_comm_status_container {
+ struct cp210x_comm_status sts; /* 0x13 bytes */
+ u8 pad_to_0x14_bytes;
+ } comm_sts_cont;
+
+ err = cp210x_get_config(port, CP210X_GET_COMM_STATUS, (unsigned int *) &comm_sts_cont, 0x13);
+
Empty line hardly needed here.
+ if (!err)
+ if (comm_sts_cont.sts.amount_in_out_queue)
Why not collapse these two *if* statements into one?
+ return false;
+ return true;
+}
+
[...]
MBR, Sergei
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