[PATCH] drv/usb: Fix the issue with Realtek USB wireless adapter AC650

[PATCH] drv/usb: Fix the issue with Realtek USB wireless adapter AC650

[tuhaowen]

Due to the dual-mode functionality of the Realtek USB wireless
adapter AC650, it initially presents itself as a flash drive
before the driver is installed.

In Linux, multi-state devices are recognized as storage devices
on startup because the driver has not yet been loaded.

As a result, the AC650 is identified as a DISK device at boot,
preventing the use of its WLAN mode. The issue can only be
resolved by unplugging and replugging the adapter.

Signed-off-by: tuhaowen <tuhaowen@uniontech.com>
---
 drivers/usb/storage/unusual_devs.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/usb/storage/unusual_devs.h b/drivers/usb/storage/unusual_devs.h
index fd68204374f2..f660d3e52436 100644
--- a/drivers/usb/storage/unusual_devs.h
+++ b/drivers/usb/storage/unusual_devs.h
@@ -1487,6 +1487,12 @@ UNUSUAL_DEV( 0x0bc2, 0x3332, 0x0000, 0x9999,
 		USB_SC_DEVICE, USB_PR_DEVICE, NULL,
 		US_FL_NO_WP_DETECT ),
 
+UNUSUAL_DEV(0x0bda, 0x1a2b, 0x0000, 0x9999,
+		"Realtek",
+		"USB Network Device",
+		USB_SC_DEVICE, USB_PR_DEVICE, NULL,
+		US_FL_IGNORE_DEVICE),
+
 UNUSUAL_DEV(  0x0d49, 0x7310, 0x0000, 0x9999,
 		"Maxtor",
 		"USB to SATA",
-- 
2.20.1

Re: [PATCH] drv/usb: Fix the issue with Realtek USB wireless adapter AC650

[Alan Stern]

On Tue, Jun 25, 2024 at 03:07:24PM +0800, tuhaowen wrote:
> Due to the dual-mode functionality of the Realtek USB wireless
> adapter AC650, it initially presents itself as a flash drive
> before the driver is installed.

Does this flash-drive mode have a real purpose?  For instance, can 
people upload new firmware by writing it to the flash drive?  I can't 
imagine that the manufacturer would have implemented the dual-mode 
functionality for no reason at all.

> In Linux, multi-state devices are recognized as storage devices
> on startup because the driver has not yet been loaded.
> 
> As a result, the AC650 is identified as a DISK device at boot,
> preventing the use of its WLAN mode. The issue can only be
> resolved by unplugging and replugging the adapter.

If there's no way to resolve this issue other than by unplugging and 
replugging the adapter, how can a patch help?

Are you sure that the problem can't be solved by a userspace helper, 
such as the usbmodeswitch program?

Alan Stern

> Signed-off-by: tuhaowen <tuhaowen@uniontech.com>
> ---
>  drivers/usb/storage/unusual_devs.h | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/usb/storage/unusual_devs.h b/drivers/usb/storage/unusual_devs.h
> index fd68204374f2..f660d3e52436 100644
> --- a/drivers/usb/storage/unusual_devs.h
> +++ b/drivers/usb/storage/unusual_devs.h
> @@ -1487,6 +1487,12 @@ UNUSUAL_DEV( 0x0bc2, 0x3332, 0x0000, 0x9999,
>  		USB_SC_DEVICE, USB_PR_DEVICE, NULL,
>  		US_FL_NO_WP_DETECT ),
>  
> +UNUSUAL_DEV(0x0bda, 0x1a2b, 0x0000, 0x9999,
> +		"Realtek",
> +		"USB Network Device",
> +		USB_SC_DEVICE, USB_PR_DEVICE, NULL,
> +		US_FL_IGNORE_DEVICE),
> +
>  UNUSUAL_DEV(  0x0d49, 0x7310, 0x0000, 0x9999,
>  		"Maxtor",
>  		"USB to SATA",
> -- 
> 2.20.1
> 
> 

Re: [PATCH] drv/usb: Fix the issue with Realtek USB wireless adapter AC650

[Lars Melin]

On 2024-06-25 14:07, tuhaowen wrote:
> Due to the dual-mode functionality of the Realtek USB wireless
> adapter AC650, it initially presents itself as a flash drive
> before the driver is installed.
> 
> In Linux, multi-state devices are recognized as storage devices
> on startup because the driver has not yet been loaded.
> 
> As a result, the AC650 is identified as a DISK device at boot,
> preventing the use of its WLAN mode. The issue can only be
> resolved by unplugging and replugging the adapter.
> 

It can be resolved by manually ejecting the created cdrom drive or by 
using usb_modeswitch which will eject the drive as soon as it is 
detected. No need for unplugging/replugging.

thanks
Lars