On Wed, May 04, 2022 at 05:16:47PM +0200, Jose Ignacio Tornos Martinez wrote:
> Some devices like 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.
>
> For these devices, 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, so a new quirk has been created. By default, quirk is
> not applied for any device and needs to be enabled by user.
>
> For these devices, 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.
>
> Signed-off-by: Jose Ignacio Tornos Martinez <jtornosm@xxxxxxxxxx>
> ---
> V4 -> V5:
> - By default, quirk is not applied for any device and needs to be enabled
> by user if necessary.
> V3 -> V4:
> - Reorder quirk entries to be in numerical order according to the vendor
> ID and product ID.
> - Add patch version information.
> V2 -> V3:
> - Change subject (Bluetooth: btusb: CSR chip hangs when unbound ->
> USB: core: skip unconfiguration if device doesn't support it).
> - Improve quirk checking.
> - Allow to test quirk interactively.
> V1 -> V2:
> - Use quirk feature for the exception.
>
> Documentation/admin-guide/kernel-parameters.txt | 2 ++
> drivers/usb/core/message.c | 12 +++++++++---
> drivers/usb/core/quirks.c | 3 +++
> include/linux/usb/quirks.h | 3 +++
> 4 files changed, 17 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 3f1cc5e317ed..71651b888d14 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -6183,6 +6183,8 @@
> pause after every control message);
> o = USB_QUIRK_HUB_SLOW_RESET (Hub needs extra
> delay after resetting its port);
> + p = USB_QUIRK_SKIP_UNCONFIGURE (device doesn't
> + support unconfigure);
> Example: quirks=0781:5580:bk,0a5c:5834:gij
>
> usbhid.mousepoll=
> diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
> index 4d59d927ae3e..9c6cd0c75f4f 100644
> --- a/drivers/usb/core/message.c
> +++ b/drivers/usb/core/message.c
> @@ -2108,9 +2108,15 @@ int usb_set_configuration(struct usb_device *dev, int configuration)
> }
> kfree(new_interfaces);
>
> - ret = usb_control_msg_send(dev, 0, USB_REQ_SET_CONFIGURATION, 0,
> - configuration, 0, NULL, 0,
> - USB_CTRL_SET_TIMEOUT, GFP_NOIO);
> + if (configuration == 0 && !cp
> + && (dev->quirks & USB_QUIRK_SKIP_UNCONFIGURE)) {
> + dev_warn(&dev->dev, "device is not unconfigured!\n");
> + ret = 0;
> + } else
> + ret = usb_control_msg_send(dev, 0, USB_REQ_SET_CONFIGURATION, 0,
> + configuration, 0, NULL, 0,
> + USB_CTRL_SET_TIMEOUT, GFP_NOIO);
> +
> if (ret && cp) {
> /*
> * All the old state is gone, so what else can we do?
> diff --git a/drivers/usb/core/quirks.c b/drivers/usb/core/quirks.c
> index d3c14b5ed4a1..f4cdf85a9eb6 100644
> --- a/drivers/usb/core/quirks.c
> +++ b/drivers/usb/core/quirks.c
> @@ -138,6 +138,9 @@ static int quirks_param_set(const char *value, const struct kernel_param *kp)
> case 'o':
> flags |= USB_QUIRK_HUB_SLOW_RESET;
> break;
> + case 'p':
> + flags |= USB_QUIRK_SKIP_UNCONFIGURE;
> + break;
> /* Ignore unrecognized flag characters */
> }
> }
> diff --git a/include/linux/usb/quirks.h b/include/linux/usb/quirks.h
> index eeb7c2157c72..79cb0616f394 100644
> --- a/include/linux/usb/quirks.h
> +++ b/include/linux/usb/quirks.h
> @@ -72,4 +72,7 @@
> /* device has endpoints that should be ignored */
> #define USB_QUIRK_ENDPOINT_IGNORE BIT(15)
>
> +/* device doesn't support unconfigure. */
> +#define USB_QUIRK_SKIP_UNCONFIGURE BIT(16)
> +
> #endif /* __LINUX_USB_QUIRKS_H */
> --
> 2.35.1
>
I'll drop this for now as there are no in-kernel users for this quirk
yet. When there is a need for one, please resubmit it.
thanks,
greg k-h
