From 09a6787fa09e8c2231ae81fa2ed3328b23d75cd2 Mon Sep 17 00:00:00 2001 From: Jan Kiszka Date: Thu, 12 Sep 2024 10:37:39 +0200 Subject: [PATCH] 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: Jan Kiszka [ johan: fix macro prefix, drop oom error message ] Signed-off-by: Johan Hovold --- drivers/usb/serial/pl2303.c | 38 ++++++++++++++++++++++++++++++++++++- 1 file changed, 37 insertions(+), 1 deletion(-) --- 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 PL2303_QUIRK_NO_BREAK_GETLINE BIT(3) static const struct usb_device_id id_table[] = { { USB_DEVICE(PL2303_VENDOR_ID, PL2303_PRODUCT_ID), @@ -469,6 +470,25 @@ static int pl2303_detect_type(struct usb 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; @@ -491,6 +511,9 @@ static int pl2303_startup(struct usb_ser 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) { @@ -727,9 +750,18 @@ static void pl2303_encode_baud_rate(stru 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); @@ -1066,9 +1098,13 @@ static int pl2303_carrier_raised(struct 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