@@ -1128,6 +1128,25 @@ dl_done_list (struct ohci_hcd *ohci)
while (td) {
struct td *td_next = td->next_dl_td;
+ struct ed *ed = td->ed;
+
+ /*
+ * Some OHCI controllers (NVIDIA for sure, maybe others)
+ * occasionally forget to add TDs to the done queue. Since
+ * TDs for a given endpoint are always processed in order,
+ * if we find a TD on the donelist then all of its
+ * predecessors must be finished as well.
+ */
+ for (;;) {
+ struct td *td2;
+
+ td2 = list_first_entry(&ed->td_list, struct td,
+ td_list);
+ if (td2 == td)
+ break;
+ takeback_td(ohci, td2);
+ }
+
takeback_td(ohci, td);
td = td_next;
}
This is a note to let you know that I have just added a patch titled USB: OHCI: workaround for hardware bug: retired TDs not to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.5.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Herton ------ From 5bda64f9a5490728e980326ab687b3bc9b3854e6 Mon Sep 17 00:00:00 2001 From: Alan Stern <stern@rowland.harvard.edu> Date: Mon, 26 Nov 2012 12:36:21 -0500 Subject: [PATCH] USB: OHCI: workaround for hardware bug: retired TDs not added to the Done Queue commit 50ce5c0683aa83eb161624ea89daa5a9eee0c2ce upstream. This patch (as1636) is a partial workaround for a hardware bug affecting OHCI controllers by NVIDIA at least, maybe others too. When the controller retires a Transfer Descriptor, it is supposed to add the TD onto the Done Queue. But sometimes this doesn't happen, with the result that ohci-hcd never realizes the corresponding transfer has finished. Symptoms can vary; a typical result is that USB audio stops working after a while. The patch works around the problem by recognizing that TDs are always processed in order. Therefore, if a later TD is found on the Done Queue than all the earlier TDs for the same endpoint must be finished as well. Unfortunately this won't solve the problem in cases where the missing TD is the last one in the endpoint's queue. A complete fix would require a signficant amount of change to the driver. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Tested-by: Oliver Neukum <oneukum@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> --- drivers/usb/host/ohci-q.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) -- 1.7.9.5