releases/2.6.32.13/usb-ehci-defer-reclamation-of-sitds.patch

   1 From 0e5f231bc16ff9910882fa5b9d64d80e7691cfab Mon Sep 17 00:00:00 2001
   2 From: Alan Stern <stern@rowland.harvard.edu>
   3 Date: Thu, 8 Apr 2010 16:56:37 -0400
   4 Subject: USB: EHCI: defer reclamation of siTDs
   5
   6 From: Alan Stern <stern@rowland.harvard.edu>
   7
   8 commit 0e5f231bc16ff9910882fa5b9d64d80e7691cfab upstream.
   9
  10 This patch (as1369) fixes a problem in ehci-hcd.  Some controllers
  11 occasionally run into trouble when the driver reclaims siTDs too
  12 quickly.  This can happen while streaming audio; it causes the
  13 controller to crash.
  14
  15 The patch changes siTD reclamation to work the same way as iTD
  16 reclamation: Completed siTDs are stored on a list and not reused until
  17 at least one frame has passed.
  18
  19 Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
  20 Tested-by: Nate Case <ncase@xes-inc.com>
  21 Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
  22
  23 ---
  24  drivers/usb/host/ehci-hcd.c   |    1 +
  25  drivers/usb/host/ehci-mem.c   |    2 +-
  26  drivers/usb/host/ehci-sched.c |   38 ++++++++++++++++++++++++++++++--------
  27  drivers/usb/host/ehci.h       |    5 +++--
  28  4 files changed, 35 insertions(+), 11 deletions(-)
  29
  30 --- a/drivers/usb/host/ehci-hcd.c
  31 +++ b/drivers/usb/host/ehci-hcd.c
  32 @@ -543,6 +543,7 @@ static int ehci_init(struct usb_hcd *hcd
  33          */
  34         ehci->periodic_size = DEFAULT_I_TDPS;
  35         INIT_LIST_HEAD(&ehci->cached_itd_list);
  36 +       INIT_LIST_HEAD(&ehci->cached_sitd_list);
  37         if ((retval = ehci_mem_init(ehci, GFP_KERNEL)) < 0)
  38                 return retval;
  39
  40 --- a/drivers/usb/host/ehci-mem.c
  41 +++ b/drivers/usb/host/ehci-mem.c
  42 @@ -136,7 +136,7 @@ static inline void qh_put (struct ehci_q
  43
  44  static void ehci_mem_cleanup (struct ehci_hcd *ehci)
  45  {
  46 -       free_cached_itd_list(ehci);
  47 +       free_cached_lists(ehci);
  48         if (ehci->async)
  49                 qh_put (ehci->async);
  50         ehci->async = NULL;
  51 --- a/drivers/usb/host/ehci-sched.c
  52 +++ b/drivers/usb/host/ehci-sched.c
  53 @@ -2127,13 +2127,27 @@ sitd_complete (
  54                         (stream->bEndpointAddress & USB_DIR_IN) ? "in" : "out");
  55         }
  56         iso_stream_put (ehci, stream);
  57 -       /* OK to recycle this SITD now that its completion callback ran. */
  58 +
  59  done:
  60         sitd->urb = NULL;
  61 -       sitd->stream = NULL;
  62 -       list_move(&sitd->sitd_list, &stream->free_list);
  63 -       iso_stream_put(ehci, stream);
  64 -
  65 +       if (ehci->clock_frame != sitd->frame) {
  66 +               /* OK to recycle this SITD now. */
  67 +               sitd->stream = NULL;
  68 +               list_move(&sitd->sitd_list, &stream->free_list);
  69 +               iso_stream_put(ehci, stream);
  70 +       } else {
  71 +               /* HW might remember this SITD, so we can't recycle it yet.
  72 +                * Move it to a safe place until a new frame starts.
  73 +                */
  74 +               list_move(&sitd->sitd_list, &ehci->cached_sitd_list);
  75 +               if (stream->refcount == 2) {
  76 +                       /* If iso_stream_put() were called here, stream
  77 +                        * would be freed.  Instead, just prevent reuse.
  78 +                        */
  79 +                       stream->ep->hcpriv = NULL;
  80 +                       stream->ep = NULL;
  81 +               }
  82 +       }
  83         return retval;
  84  }
  85
  86 @@ -2199,9 +2213,10 @@ done:
  87
  88  /*-------------------------------------------------------------------------*/
  89
  90 -static void free_cached_itd_list(struct ehci_hcd *ehci)
  91 +static void free_cached_lists(struct ehci_hcd *ehci)
  92  {
  93         struct ehci_itd *itd, *n;
  94 +       struct ehci_sitd *sitd, *sn;
  95
  96         list_for_each_entry_safe(itd, n, &ehci->cached_itd_list, itd_list) {
  97                 struct ehci_iso_stream  *stream = itd->stream;
  98 @@ -2209,6 +2224,13 @@ static void free_cached_itd_list(struct
  99                 list_move(&itd->itd_list, &stream->free_list);
 100                 iso_stream_put(ehci, stream);
 101         }
 102 +
 103 +       list_for_each_entry_safe(sitd, sn, &ehci->cached_sitd_list, sitd_list) {
 104 +               struct ehci_iso_stream  *stream = sitd->stream;
 105 +               sitd->stream = NULL;
 106 +               list_move(&sitd->sitd_list, &stream->free_list);
 107 +               iso_stream_put(ehci, stream);
 108 +       }
 109  }
 110
 111  /*-------------------------------------------------------------------------*/
 112 @@ -2235,7 +2257,7 @@ scan_periodic (struct ehci_hcd *ehci)
 113                 clock_frame = -1;
 114         }
 115         if (ehci->clock_frame != clock_frame) {
 116 -               free_cached_itd_list(ehci);
 117 +               free_cached_lists(ehci);
 118                 ehci->clock_frame = clock_frame;
 119         }
 120         clock %= mod;
 121 @@ -2398,7 +2420,7 @@ restart:
 122                         clock = now;
 123                         clock_frame = clock >> 3;
 124                         if (ehci->clock_frame != clock_frame) {
 125 -                               free_cached_itd_list(ehci);
 126 +                               free_cached_lists(ehci);
 127                                 ehci->clock_frame = clock_frame;
 128                         }
 129                 } else {
 130 --- a/drivers/usb/host/ehci.h
 131 +++ b/drivers/usb/host/ehci.h
 132 @@ -87,8 +87,9 @@ struct ehci_hcd {                     /* one per controlle
 133         int                     next_uframe;    /* scan periodic, start here */
 134         unsigned                periodic_sched; /* periodic activity count */
 135
 136 -       /* list of itds completed while clock_frame was still active */
 137 +       /* list of itds & sitds completed while clock_frame was still active */
 138         struct list_head        cached_itd_list;
 139 +       struct list_head        cached_sitd_list;
 140         unsigned                clock_frame;
 141
 142         /* per root hub port */
 143 @@ -195,7 +196,7 @@ timer_action_done (struct ehci_hcd *ehci
 144         clear_bit (action, &ehci->actions);
 145  }
 146
 147 -static void free_cached_itd_list(struct ehci_hcd *ehci);
 148 +static void free_cached_lists(struct ehci_hcd *ehci);
 149
 150  /*-------------------------------------------------------------------------*/
 151