diff options
Diffstat (limited to 'drivers/usb/class/usblp.c')
| -rw-r--r-- | drivers/usb/class/usblp.c | 40 |
1 files changed, 30 insertions, 10 deletions
diff --git a/drivers/usb/class/usblp.c b/drivers/usb/class/usblp.c index 71c2ae4b8106..582099f4f449 100644 --- a/drivers/usb/class/usblp.c +++ b/drivers/usb/class/usblp.c @@ -289,8 +289,25 @@ static int usblp_ctrl_msg(struct usblp *usblp, int request, int type, int dir, i #define usblp_reset(usblp)\ usblp_ctrl_msg(usblp, USBLP_REQ_RESET, USB_TYPE_CLASS, USB_DIR_OUT, USB_RECIP_OTHER, 0, NULL, 0) -#define usblp_hp_channel_change_request(usblp, channel, buffer) \ - usblp_ctrl_msg(usblp, USBLP_REQ_HP_CHANNEL_CHANGE_REQUEST, USB_TYPE_VENDOR, USB_DIR_IN, USB_RECIP_INTERFACE, channel, buffer, 1) +static int usblp_hp_channel_change_request(struct usblp *usblp, int channel, u8 *new_channel) +{ + u8 *buf; + int ret; + + buf = kzalloc(1, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + ret = usblp_ctrl_msg(usblp, USBLP_REQ_HP_CHANNEL_CHANGE_REQUEST, + USB_TYPE_VENDOR, USB_DIR_IN, USB_RECIP_INTERFACE, + channel, buf, 1); + if (ret == 0) + *new_channel = buf[0]; + + kfree(buf); + + return ret; +} /* * See the description for usblp_select_alts() below for the usage @@ -1332,14 +1349,17 @@ static int usblp_set_protocol(struct usblp *usblp, int protocol) if (protocol < USBLP_FIRST_PROTOCOL || protocol > USBLP_LAST_PROTOCOL) return -EINVAL; - alts = usblp->protocol[protocol].alt_setting; - if (alts < 0) - return -EINVAL; - r = usb_set_interface(usblp->dev, usblp->ifnum, alts); - if (r < 0) { - printk(KERN_ERR "usblp: can't set desired altsetting %d on interface %d\n", - alts, usblp->ifnum); - return r; + /* Don't unnecessarily set the interface if there's a single alt. */ + if (usblp->intf->num_altsetting > 1) { + alts = usblp->protocol[protocol].alt_setting; + if (alts < 0) + return -EINVAL; + r = usb_set_interface(usblp->dev, usblp->ifnum, alts); + if (r < 0) { + printk(KERN_ERR "usblp: can't set desired altsetting %d on interface %d\n", + alts, usblp->ifnum); + return r; + } } usblp->bidir = (usblp->protocol[protocol].epread != NULL); |