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) &&
+ (usb_pipecontrol(urb->pipe) || usb_pipebulk(urb->pipe)) &&
+ urb->dev->tt)
+ 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.
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