[PATCH net-next] net: usb: cdc_ncm: add Apple Silicon MacBook Air (05ac:1903) device ID

[PATCH net-next] net: usb: cdc_ncm: add Apple Silicon MacBook Air (05ac:1903) device ID

[Divyanshu Jha]

The Apple Silicon MacBook Air exposes a CDC-NCM interface (05ac:1903)
when connected host-to-host over USB-C.

Like other Apple CDC-NCM peripherals (0x1902 and 0x1905), Apple's
firmware omits the CDC status interrupt endpoint. This causes the
standard cdc_ncm probe to fail with a missing endpoint error.

Add device ID 05ac:1903 to cdc_ncm_devs binding to
apple_private_interface_info so the driver bypasses the interrupt
check and initializes host-to-host networking successfully.

Signed-off-by: Divyanshu Jha <divyanshuj2006@gmail.com>
---
 drivers/net/usb/cdc_ncm.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c
index 35db38cb3..6848b9421 100644
--- a/drivers/net/usb/cdc_ncm.c
+++ b/drivers/net/usb/cdc_ncm.c
@@ -2019,6 +2019,12 @@ static const struct usb_device_id cdc_devs[] = {
 	{ USB_DEVICE_INTERFACE_NUMBER(0x05ac, 0x1902, 2),
 		.driver_info = (unsigned long)&apple_private_interface_info,
 	},
+	{ USB_DEVICE_INTERFACE_NUMBER(0x05ac, 0x1903, 0),
+		.driver_info = (unsigned long)&apple_private_interface_info,
+	},
+	{ USB_DEVICE_INTERFACE_NUMBER(0x05ac, 0x1903, 2),
+		.driver_info = (unsigned long)&apple_private_interface_info,
+	},
 	{ USB_DEVICE_INTERFACE_NUMBER(0x05ac, 0x1905, 0),
 		.driver_info = (unsigned long)&apple_private_interface_info,
 	},
-- 
2.47.3

Re: [PATCH net-next] net: usb: cdc_ncm: add Apple Silicon MacBook Air (05ac:1903) device ID

[Nicolai Buchwitz]

Hi Divyanshu

On 23.10.2026 09:04, Divyanshu Jha wrote:
> The Apple Silicon MacBook Air exposes a CDC-NCM interface (05ac:1903)
> when connected host-to-host over USB-C.

Which model and chip? a5148bc2fa27 says the MacBook Air shows up as
0x1905, and the Mac PIDs so far (0x1901/0x1902/0x1905) seem to follow
the SoC generation, not the product line?

Please add the lsusb -v or ioreg output for 0x1903 and the dmesg lines
you saw, like the 0x1902 commit did.

> 
> Like other Apple CDC-NCM peripherals (0x1902 and 0x1905), Apple's
> firmware omits the CDC status interrupt endpoint. This causes the
> standard cdc_ncm probe to fail with a missing endpoint error.
> 
> Add device ID 05ac:1903 to cdc_ncm_devs binding to

nit: cdc_ncm_devs -> cdc_devs

> apple_private_interface_info so the driver bypasses the interrupt
> check and initializes host-to-host networking successfully.
> 
> Signed-off-by: Divyanshu Jha <divyanshuj2006@gmail.com>
> ---
>  drivers/net/usb/cdc_ncm.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c
> index 35db38cb3..6848b9421 100644
> --- a/drivers/net/usb/cdc_ncm.c
> +++ b/drivers/net/usb/cdc_ncm.c
> @@ -2019,6 +2019,12 @@ static const struct usb_device_id cdc_devs[] = {
>  	{ USB_DEVICE_INTERFACE_NUMBER(0x05ac, 0x1902, 2),
>  		.driver_info = (unsigned long)&apple_private_interface_info,
>  	},
> +	{ USB_DEVICE_INTERFACE_NUMBER(0x05ac, 0x1903, 0),
> +		.driver_info = (unsigned long)&apple_private_interface_info,
> +	},
> +	{ USB_DEVICE_INTERFACE_NUMBER(0x05ac, 0x1903, 2),
> +		.driver_info = (unsigned long)&apple_private_interface_info,
> +	},
>  	{ USB_DEVICE_INTERFACE_NUMBER(0x05ac, 0x1905, 0),
>  		.driver_info = (unsigned long)&apple_private_interface_info,
>  	},

Please note that net-next is closed during the 7.4 merge window [1].
So please wait until it's open again, before you re-spin.

[1] https://netdev.bots.linux.dev/net-next.html

Thanks,
Nicolai

Re: [PATCH net-next] net: usb: cdc_ncm: add Apple Silicon MacBook Air (05ac:1903) device ID

[Nicolai Buchwitz]

On 23.10.2026 15:44, divyanshu jha wrote:
> The device tested is an Apple MacBook Air (13-inch, M1, 2020), Model
> A2337
> (MacBookAir10,1) with an Apple M1 chip.

Thanks for the clarification. Please add the tested HW + their VID/PID 
snippet
from lsusb to the commit / cover. This will prevent further questions 
from the
netdev AI bots :-)

> [...]

With the nit changed + details (you can my the tag in the re-spin):

Reviewed-by: Nicolai Buchwitz <nb@tipi-net.de>

Thanks,
Nicolai