From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932182AbcBWWEO (ORCPT ); Tue, 23 Feb 2016 17:04:14 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:41586 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755357AbcBWVos (ORCPT ); Tue, 23 Feb 2016 16:44:48 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Greg Kroah-Hartman" , "Mathias Nyman" Date: Tue, 23 Feb 2016 21:42:03 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 40/67] Revert "xhci: don't finish a TD if we get a short-transfer event mid TD" In-Reply-To: X-SA-Exim-Connect-IP: 92.40.248.141 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.78-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Mathias Nyman commit a6835090716a85f2297668ba593bd00e1051e662 upstream. This reverts commit e210c422b6fd ("xhci: don't finish a TD if we get a short transfer event mid TD") Turns out that most host controllers do not follow the xHCI specs and never send the second event for the last TRB in the TD if there was a short event mid-TD. Returning the URB directly after the first short-transfer event is far better than never returning the URB. (class drivers usually timeout after 30sec). For the hosts that do send the second event we will go back to treating it as misplaced event and print an error message for it. The origial patch was sent to stable kernels and needs to be reverted from there as well Signed-off-by: Mathias Nyman Signed-off-by: Greg Kroah-Hartman [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- drivers/usb/host/xhci-ring.c | 10 ---------- 1 file changed, 10 deletions(-) diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index f1c21c40b4a6..3915657e6078 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -2187,10 +2187,6 @@ EVENT_TRB_LEN(le32_to_cpu(event->transfer_len))); /* Fast path - was this the last TRB in the TD for this URB? */ if (event_trb == td->last_trb) { - if (td->urb_length_set && trb_comp_code == COMP_SHORT_TX) - return finish_td(xhci, td, event_trb, event, ep, - status, false); - if (EVENT_TRB_LEN(le32_to_cpu(event->transfer_len)) != 0) { td->urb->actual_length = td->urb->transfer_buffer_length - @@ -2242,12 +2238,6 @@ td->urb->actual_length += TRB_LEN(le32_to_cpu(cur_trb->generic.field[2])) - EVENT_TRB_LEN(le32_to_cpu(event->transfer_len)); - - if (trb_comp_code == COMP_SHORT_TX) { - xhci_dbg(xhci, "mid bulk/intr SP, wait for last TRB event\n"); - td->urb_length_set = true; - return 0; - } } return finish_td(xhci, td, event_trb, event, ep, status, false);