Re: [PATCH v4 2/2] USB: serial: blacklist USB-UIRT when driver is selected

On Thu, Jun 10, 2021 at 12:23:53PM +0200, Greg Kroah-Hartman wrote:

On Thu, Jun 10, 2021 at 11:16:25AM +0100, Sean Young wrote:

quoted

The USB-UIRT device has its own driver, so blacklist the fdti driver
from using it if the driver has been enabled.

Signed-off-by: Sean Young <sean@mess.org>
---
 drivers/usb/serial/ftdi_sio.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index 369ef140df78..2e9a9076a38d 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c

@@ -106,7 +106,7 @@ static const struct ftdi_sio_quirk ftdi_NDI_device_quirk = {
 	.probe	= ftdi_NDI_device_setup,
 };
 
-static const struct ftdi_sio_quirk ftdi_USB_UIRT_quirk = {
+static __maybe_unused const struct ftdi_sio_quirk ftdi_USB_UIRT_quirk = {

Why make this change?

If CONFIG_IR_UIRT is enabled, then this struct is not used. This generates
a warning when compiling with W=1 (clang or gcc):

  CC [M]  drivers/usb/serial/ftdi_sio.o
drivers/usb/serial/ftdi_sio.c:109:36: warning: ‘ftdi_USB_UIRT_quirk’ defined but not used [-Wunused-const-variable=]
  109 | static const struct ftdi_sio_quirk ftdi_USB_UIRT_quirk = {
      |                                    ^~~~~~~~~~~~~~~~~~~

quoted

 	.port_probe = ftdi_USB_UIRT_setup,
 };
 

@@ -568,8 +568,10 @@ static const struct usb_device_id id_table_combined[] = {
 	{ USB_DEVICE(OCT_VID, OCT_DK201_PID) },
 	{ USB_DEVICE(FTDI_VID, FTDI_HE_TIRA1_PID),
 		.driver_info = (kernel_ulong_t)&ftdi_HE_TIRA1_quirk },
+#if !IS_ENABLED(CONFIG_IR_UIRT)
 	{ USB_DEVICE(FTDI_VID, FTDI_USB_UIRT_PID),
 		.driver_info = (kernel_ulong_t)&ftdi_USB_UIRT_quirk },
+#endif
 	{ USB_DEVICE(FTDI_VID, PROTEGO_SPECIAL_1) },
 	{ USB_DEVICE(FTDI_VID, PROTEGO_R2X0) },
 	{ USB_DEVICE(FTDI_VID, PROTEGO_SPECIAL_3) },

@@ -2281,7 +2283,7 @@ static int ftdi_sio_port_probe(struct usb_serial_port *port)
 /* Setup for the USB-UIRT device, which requires hardwired
  * baudrate (38400 gets mapped to 312500) */
 /* Called from usbserial:serial_probe */
-static void ftdi_USB_UIRT_setup(struct ftdi_private *priv)
+static __maybe_unused void ftdi_USB_UIRT_setup(struct ftdi_private *priv)

Again, why this change here?

Same again.


Thanks for reviewing.

Sean