Commit 40827729 authored by Jan Kiszka's avatar Jan Kiszka Committed by Johan Hovold
Browse files

USB: serial: pl2303: account for deficits of clones 



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: default avatarJan Kiszka <jan.kiszka@siemens.com>
[ johan: fix macro prefix, drop oom error message ]
Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
parent 59b723cd

drivers/usb/serial/pl2303.c

+37 −1
Original line number Diff line number Diff line
@@ -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 PL2303_QUIRK_NO_BREAK_GETLINE		BIT(3)



static const struct usb_device_id id_table[] = {

	{ USB_DEVICE(PL2303_VENDOR_ID, PL2303_PRODUCT_ID),
@@ -467,6 +468,25 @@ 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)

		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;
@@ -489,6 +509,9 @@ 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 |= PL2303_QUIRK_NO_BREAK_GETLINE;



	usb_set_serial_data(serial, spriv);



	if (type != TYPE_HXN) {
@@ -725,9 +748,18 @@ 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 & PL2303_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);
@@ -1064,9 +1096,13 @@ 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 & PL2303_QUIRK_NO_BREAK_GETLINE)

		return -ENOTTY;



	if (enable)

		state = BREAK_ON;

	else