Nak. The UAS driver isn't ready for prime time. Until we get the error
paths cleaned up (and I know I owe Greg some patches for 3.4 from both
of us), I don't want the UAS driver to claim devices with BOT on the
first alternate setting. So keep this patch for a bit. :)
Sarah Sharp
On Fri, Jan 13, 2012 at 09:59:37PM +0100, Sebastian Andrzej Siewior wrote:
> For UAS we use an alternative driver. A device might show as
> USB_CLASS_MASS_STORAGE, USB_SC_SCSI, USB_PR_BULK on alt setting 0. and
> have USB_PR_UAS on alt setting 1. In that case we do not want to bind to
> the device and let the UAS driver to pick it up.
> There is one requirement by the UAS driver: sg support in HCD. If this
> is not possible then we keep the device and inform the user.
>
> Cc: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
> Cc: Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx>
> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
> ---
> drivers/usb/storage/usb.c | 48 +++++++++++++++++++++++++++++++++++++++++++++
> 1 files changed, 48 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/usb/storage/usb.c b/drivers/usb/storage/usb.c
> index 9e069ef..4216869 100644
> --- a/drivers/usb/storage/usb.c
> +++ b/drivers/usb/storage/usb.c
> @@ -1022,6 +1022,50 @@ void usb_stor_disconnect(struct usb_interface *intf)
> }
> EXPORT_SYMBOL_GPL(usb_stor_disconnect);
>
> +#if defined(CONFIG_USB_UAS) || defined(CONFIG_USB_UAS_MODULE)
> +static int uas_is_interface(struct usb_host_interface *intf)
> +{
> + return (intf->desc.bInterfaceClass == USB_CLASS_MASS_STORAGE &&
> + intf->desc.bInterfaceSubClass == USB_SC_SCSI &&
> + intf->desc.bInterfaceProtocol == USB_PR_UAS);
> +}
> +
> +static int stor_check_for_uas(struct usb_interface *intf)
> +{
> + struct usb_device *udev = interface_to_usbdev(intf);
> + int sg_supported = udev->bus->sg_tablesize != 0;
> + int i;
> +
> + for (i = 0; i < intf->num_altsetting; i++) {
> + struct usb_host_interface *alt = &intf->altsetting[i];
> +
> + if (uas_is_interface(alt)) {
> + if (!sg_supported) {
> + dev_warn(&udev->dev,
> + "Device provides UAS function which can not be used "
> + "because this USB controller does not support\n");
> + dev_warn(&udev->dev,
> + "scatter-gather. Using legacy interface.\n");
> + return 0;
> + } else {
> + dev_warn(&udev->dev,
> + "Releasing the device in favour of the UAS driver\n");
> + return 1;
> + }
> + }
> + }
> + return 0;
> +}
> +
> +#else
> +
> +static inline int stor_check_for_uas(struct usb_interface *intf)
> +{
> + return 0;
> +}
> +
> +#endif
> +
> /* The main probe routine for standard devices */
> static int storage_probe(struct usb_interface *intf,
> const struct usb_device_id *id)
> @@ -1039,6 +1083,10 @@ static int storage_probe(struct usb_interface *intf,
> usb_usual_ignore_device(intf))
> return -ENXIO;
>
> + result = stor_check_for_uas(intf);
> + if (result)
> + return -ENXIO;
> +
> /*
> * Call the general probe procedures.
> *
> --
> 1.7.8.3
>
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