On 18.01.2021 0:36, Jeremy Figgins wrote:
Certain devices such as Winbond Virtual Com Port,
which is used in some usb printers, will stop
responding after the usb_control_msg_send()
Hm, not usblp_set_protocol()?
calls in usb_set_interface(). These devices work
fine without having usb_set_interface() called, so
this flag prevents that call.
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.
Perhaps the handling of that flag should just be extended to yuor case?
Signed-off-by: Jeremy Figgins <kernel@xxxxxxxxxxxxxxxxx>
---
drivers/usb/class/usblp.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/class/usblp.c b/drivers/usb/class/usblp.c
index 134dc2005ce9..6e2d58813d7d 100644
--- a/drivers/usb/class/usblp.c
+++ b/drivers/usb/class/usblp.c
[...]
@@ -1332,7 +1334,11 @@ 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->quirks & USBLP_QUIRK_NO_SET_INTF) {
+ r = 0;
+ } else {
+ r = usb_set_interface(usblp->dev, usblp->ifnum, alts);
+ }
The braces above not needed at all.
[...]
MBR, Sergei
