Hi, On Wed, Nov 01, 2017 at 06:31:16PM +0000, Gervais, Francois wrote: > We are running the musb driver on a AM335 cpu paired with a microchip hub (USB2412). > > In one of our use-cases, we have a high chance of having an error on a bulk split transaction. Since the musb driver does not implement the clear TT buffer it leaves us with a TT buffer full on the hub which in turns NAK any new split transactions. > > To fix this problem, we added the Clear_TT_Buffer handling in case of a split transaction error, trying to match the spec as closely as possible. > > We came up with the following: > > diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c > index 26bda88..ac1a959 100755 > --- a/drivers/usb/musb/musb_host.c > +++ b/drivers/usb/musb/musb_host.c > @@ -376,6 +376,11 @@ static void musb_advance_schedule(struct musb *musb, struct urb *urb, > break; > } > > + if ((status || urb->unlinked) && Did you case hit on status (what is the error code?) or urb->unlinked? or both? > + (usb_pipecontrol(urb->pipe) || usb_pipebulk(urb->pipe)) && > + urb->dev->tt) Better to put urb->dev->tt as the very first condition check to make the whole checking efficient. I would think you also have to check if tt->hub != roothub? Since musb virtual hub doesn't support TT, I am not sure what will happen if trying to clear TT buffer on musb virtual hub. > + usb_hub_clear_tt_buffer(urb); > + > qh->is_ready = 0; > musb_giveback(musb, urb, status); > qh->is_ready = ready; > > This seems to work in our case but we'd like to get feedback in order to improve the patch if needed. Regards, -Bin. -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
