From: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
There are apparently incomplete clones of the HXD type chip in use.
Those return -EPIPE on GET_LINE_REQUEST and BREAK_REQUEST. Avoid
flooding the kernel log with those errors. Detect them during startup
and then use the line_settings cache instead of GET_LINE_REQUEST. Signal
missing break support via -ENOTTY.
Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
---
Changes in v3:
- use quirks field instead of new type (suggested by Michal)
drivers/usb/serial/pl2303.c | 41 ++++++++++++++++++++++++++++++++++++-
1 file changed, 40 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/serial/pl2303.c b/drivers/usb/serial/pl2303.c
index d93f5d584557..bc433178a6b0 100644
--- a/drivers/usb/serial/pl2303.c
+++ b/drivers/usb/serial/pl2303.c
@@ -31,6 +31,7 @@
#define PL2303_QUIRK_UART_STATE_IDX0 BIT(0)
#define PL2303_QUIRK_LEGACY BIT(1)
#define PL2303_QUIRK_ENDPOINT_HACK BIT(2)
+#define PL2304_QUIRK_NO_BREAK_GETLINE BIT(3)
static const struct usb_device_id id_table[] = {
{ USB_DEVICE(PL2303_VENDOR_ID, PL2303_PRODUCT_ID),
@@ -466,6 +467,28 @@ static int pl2303_detect_type(struct usb_serial *serial)
return -ENODEV;
}
+static bool pl2303_is_hxd_clone(struct usb_serial *serial)
+{
+ struct usb_device *udev = serial->dev;
+ unsigned char *buf;
+ int ret;
+
+ buf = kmalloc(7, GFP_KERNEL);
+ if (!buf) {
+ dev_err(&serial->interface->dev,
+ "could not check for clone type, not enough memory\n");
+ return false;
+ }
+
+ ret = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
+ GET_LINE_REQUEST, GET_LINE_REQUEST_TYPE,
+ 0, 0, buf, 7, 100);
+
+ kfree(buf);
+
+ return ret == -EPIPE;
+}
+
static int pl2303_startup(struct usb_serial *serial)
{
struct pl2303_serial_private *spriv;
@@ -488,6 +511,9 @@ static int pl2303_startup(struct usb_serial *serial)
spriv->quirks = (unsigned long)usb_get_serial_data(serial);
spriv->quirks |= spriv->type->quirks;
+ if (type == TYPE_HXD && pl2303_is_hxd_clone(serial))
+ spriv->quirks |= PL2304_QUIRK_NO_BREAK_GETLINE;
+
usb_set_serial_data(serial, spriv);
if (type != TYPE_HXN) {
@@ -724,9 +750,18 @@ static void pl2303_encode_baud_rate(struct tty_struct *tty,
static int pl2303_get_line_request(struct usb_serial_port *port,
unsigned char buf[7])
{
- struct usb_device *udev = port->serial->dev;
+ struct usb_serial *serial = port->serial;
+ struct pl2303_serial_private *spriv = usb_get_serial_data(serial);
+ struct usb_device *udev = serial->dev;
int ret;
+ if (spriv->quirks & PL2304_QUIRK_NO_BREAK_GETLINE) {
+ struct pl2303_private *priv = usb_get_serial_port_data(port);
+
+ memcpy(buf, priv->line_settings, 7);
+ return 0;
+ }
+
ret = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
GET_LINE_REQUEST, GET_LINE_REQUEST_TYPE,
0, 0, buf, 7, 100);
@@ -1063,9 +1098,13 @@ static int pl2303_carrier_raised(struct usb_serial_port *port)
static int pl2303_set_break(struct usb_serial_port *port, bool enable)
{
struct usb_serial *serial = port->serial;
+ struct pl2303_serial_private *spriv = usb_get_serial_data(serial);
u16 state;
int result;
+ if (spriv->quirks & PL2304_QUIRK_NO_BREAK_GETLINE)
+ return -ENOTTY;
+
if (enable)
state = BREAK_ON;
else
--
2.43.0
