Re: [PATCH] Bluetooth: btusb: CSR chip hangs when unbound

[Greg KH <gregkh@linuxfoundation.org>]

On Mon, May 02, 2022 at 09:07:58AM +0200, Jose Ignacio Tornos Martinez wrote:
> Bluetooth Dongles with CSR chip (i.e. USB Bluetooth V4.0 Dongle by
> Trust) hang when they are unbound from 'unbind' sysfs entry and
> can not be bound again.
> 
> The reason is CSR chip hangs when usb configuration command with
> index 0 (used to unconfigure) is sent during disconnection.
> 
> To avoid this unwanted result, it is necessary not to send this
> command for CSR chip when usb device is unbound, so a new quirk
> has been created for this device.
> 
> Athough device is not unconfigured, it is better to avoid device
> hanging to be able to operate. Even bluetooth can be previously
> turned off.
> On the other hand, this is not important if usb device is going to
> be bound again (normal behavior), i.e. with usbip.
> ---
>  drivers/usb/core/generic.c | 3 ++-
>  drivers/usb/core/quirks.c  | 3 +++
>  include/linux/usb/quirks.h | 3 +++
>  3 files changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/core/generic.c b/drivers/usb/core/generic.c
> index 740342a2812a..ea770b83d876 100644
> --- a/drivers/usb/core/generic.c
> +++ b/drivers/usb/core/generic.c
> @@ -22,6 +22,7 @@
>  #include <linux/usb.h>
>  #include <linux/usb/hcd.h>
>  #include <uapi/linux/usb/audio.h>
> +#include <linux/usb/quirks.h>

Shouldn't that be above the uapi include?

>  #include "usb.h"
>  
>  static inline const char *plural(int n)
> @@ -256,7 +257,7 @@ void usb_generic_driver_disconnect(struct usb_device *udev)
>  
>  	/* if this is only an unbind, not a physical disconnect, then
>  	 * unconfigure the device */
> -	if (udev->actconfig)
> +	if (!(udev->quirks & USB_QUIRK_SKIP_UNCONFIGURE) && udev->actconfig)
>  		usb_set_configuration(udev, -1);
>  }
>  
> diff --git a/drivers/usb/core/quirks.c b/drivers/usb/core/quirks.c
> index d3c14b5ed4a1..13989629d743 100644
> --- a/drivers/usb/core/quirks.c
> +++ b/drivers/usb/core/quirks.c
> @@ -510,6 +510,9 @@ static const struct usb_device_id usb_quirk_list[] = {
>  	/* INTEL VALUE SSD */
>  	{ USB_DEVICE(0x8086, 0xf1a5), .driver_info = USB_QUIRK_RESET_RESUME },
>  
> +	/* CSR Bluetooth */
> +	{ USB_DEVICE(0x0a12, 0x0001), .driver_info = USB_QUIRK_SKIP_UNCONFIGURE },

Please read the big comment at the top of this list of entries.  It says
it must be in sorder order, which this is not :(

thanks,

greg k-h