From f349e0b3ac12cfed000acd4db144883848d60f1c Mon Sep 17 00:00:00 2001 From: Aleksander Morgado Date: Fri, 6 Mar 2015 17:14:21 +0200 Subject: [PATCH] xhci: fix reporting of 0-sized URBs in control endpoint commit 45ba2154d12fc43b70312198ec47085f10be801a upstream. When a control transfer has a short data stage, the xHCI controller generates two transfer events: a COMP_SHORT_TX event that specifies the untransferred amount, and a COMP_SUCCESS event. But when the data stage is not short, only the COMP_SUCCESS event occurs. Therefore, xhci-hcd must set urb->actual_length to urb->transfer_buffer_length while processing the COMP_SUCCESS event, unless urb->actual_length was set already by a previous COMP_SHORT_TX event. The driver checks this by seeing whether urb->actual_length == 0, but this alone is the wrong test, as it is entirely possible for a short transfer to have an urb->actual_length = 0. This patch changes the xhci driver to rely on a new td->urb_length_set flag, which is set to true when a COMP_SHORT_TX event is received and the URB length updated at that stage. This fixes a bug which affected the HSO plugin, which relies on URBs with urb->actual_length == 0 to halt re-submitting the RX URB in the control endpoint. Signed-off-by: Aleksander Morgado Signed-off-by: Mathias Nyman Signed-off-by: Greg Kroah-Hartman Signed-off-by: Ben Hutchings --- Reading git-format-patch failed