On Sun, 17 Jan 2021 15:36:39 -0600 Jeremy Figgins <kernel@xxxxxxxxxxxxxxxxx> wrote: > The naming is designed to mirror the existing > USB_QUIRK_NO_SET_INTF flag, but that flag is > not sufficient to make these devices work. > + { 0x0416, 0x5011, USBLP_QUIRK_NO_SET_INTF }, /* Winbond Electronics Corp. Virtual Com Port */ Jeremy, thanks for the patch. It looks mostly fine code-wise (quirk is out of numerical order), but I have a question: did you consider keying off usblp->dev->quirks instead? How about this: diff --git a/drivers/usb/class/usblp.c b/drivers/usb/class/usblp.c index 37062130a03c..0c4a98f00797 100644 --- a/drivers/usb/class/usblp.c +++ b/drivers/usb/class/usblp.c @@ -1315,7 +1315,11 @@ static int usblp_set_protocol(struct usblp *usblp, int protocol) alts = usblp->protocol[protocol].alt_setting; if (alts < 0) return -EINVAL; - r = usb_set_interface(usblp->dev, usblp->ifnum, alts); + if (usblp->dev->quirks & USB_QUIRK_NO_SET_INTF) { + r = 0; + } else { + 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); diff --git a/drivers/usb/core/quirks.c b/drivers/usb/core/quirks.c index 1b4eb7046b07..632c60401d53 100644 --- a/drivers/usb/core/quirks.c +++ b/drivers/usb/core/quirks.c @@ -205,6 +205,9 @@ static const struct usb_device_id usb_quirk_list[] = { /* HP v222w 16GB Mini USB Drive */ { USB_DEVICE(0x03f0, 0x3f40), .driver_info = USB_QUIRK_DELAY_INIT }, + /* Winbond Electronics Corp. Virtual Com Port */ + { USB_DEVICE(0x0416, 0x5011), .driver_info = USB_QUIRK_NO_SET_INTF }, + /* Creative SB Audigy 2 NX */ { USB_DEVICE(0x041e, 0x3020), .driver_info = USB_QUIRK_RESET_RESUME }, Please let me know if it works for you. -- Pete