path: root/drivers/usb/core/hub.c
diff options
authorAlan Stern <stern@rowland.harvard.edu>2009-06-29 10:43:32 -0400
committerGreg Kroah-Hartman <gregkh@suse.de>2009-07-12 15:16:38 -0700
commitcb88a1b887bb8908f6e00ce29e893ea52b074940 (patch)
tree198cba7974836d994cfc839b95242e8321702d5c /drivers/usb/core/hub.c
parent87ea8c887905d8b13ae90b537117592ed027632a (diff)
USB: fix the clear_tt_buffer interface
This patch (as1255) updates the interface for calling usb_hub_clear_tt_buffer(). Even the name of the function is changed! When an async URB (i.e., Control or Bulk) going through a high-speed hub to a non-high-speed device is cancelled or fails, the hub's Transaction Translator buffer may be left busy still trying to complete the transaction. The buffer has to be cleared; that's what usb_hub_clear_tt_buffer() does. It isn't safe to send any more URBs to the same endpoint until the TT buffer is fully clear. Therefore the HCD needs to be told when the Clear-TT-Buffer request has finished. This patch adds a callback method to struct hc_driver for that purpose, and makes the hub driver invoke the callback at the proper time. The patch also changes a couple of names; "hub_tt_kevent" and "tt.kevent" now look rather antiquated. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Cc: stable <stable@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb/core/hub.c')
1 files changed, 26 insertions, 14 deletions
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 2af3b4f0605..71f86c60d83 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -450,10 +450,10 @@ hub_clear_tt_buffer (struct usb_device *hdev, u16 devinfo, u16 tt)
* talking to TTs must queue control transfers (not just bulk and iso), so
* both can talk to the same hub concurrently.
-static void hub_tt_kevent (struct work_struct *work)
+static void hub_tt_work(struct work_struct *work)
struct usb_hub *hub =
- container_of(work, struct usb_hub, tt.kevent);
+ container_of(work, struct usb_hub, tt.clear_work);
unsigned long flags;
int limit = 100;
@@ -462,6 +462,7 @@ static void hub_tt_kevent (struct work_struct *work)
struct list_head *next;
struct usb_tt_clear *clear;
struct usb_device *hdev = hub->hdev;
+ const struct hc_driver *drv;
int status;
next = hub->tt.clear_list.next;
@@ -471,21 +472,25 @@ static void hub_tt_kevent (struct work_struct *work)
/* drop lock so HCD can concurrently report other TT errors */
spin_unlock_irqrestore (&hub->tt.lock, flags);
status = hub_clear_tt_buffer (hdev, clear->devinfo, clear->tt);
- spin_lock_irqsave (&hub->tt.lock, flags);
if (status)
dev_err (&hdev->dev,
"clear tt %d (%04x) error %d\n",
clear->tt, clear->devinfo, status);
+ /* Tell the HCD, even if the operation failed */
+ drv = clear->hcd->driver;
+ if (drv->clear_tt_buffer_complete)
+ (drv->clear_tt_buffer_complete)(clear->hcd, clear->ep);
+ spin_lock_irqsave(&hub->tt.lock, flags);
spin_unlock_irqrestore (&hub->tt.lock, flags);
- * usb_hub_tt_clear_buffer - clear control/bulk TT state in high speed hub
- * @udev: the device whose split transaction failed
- * @pipe: identifies the endpoint of the failed transaction
+ * usb_hub_clear_tt_buffer - clear control/bulk TT state in high speed hub
+ * @urb: an URB associated with the failed or incomplete split transaction
* High speed HCDs use this to tell the hub driver that some split control or
* bulk transaction failed in a way that requires clearing internal state of
@@ -495,8 +500,10 @@ static void hub_tt_kevent (struct work_struct *work)
* It may not be possible for that hub to handle additional full (or low)
* speed transactions until that state is fully cleared out.
-void usb_hub_tt_clear_buffer (struct usb_device *udev, int pipe)
+int usb_hub_clear_tt_buffer(struct urb *urb)
+ struct usb_device *udev = urb->dev;
+ int pipe = urb->pipe;
struct usb_tt *tt = udev->tt;
unsigned long flags;
struct usb_tt_clear *clear;
@@ -508,7 +515,7 @@ void usb_hub_tt_clear_buffer (struct usb_device *udev, int pipe)
if ((clear = kmalloc (sizeof *clear, GFP_ATOMIC)) == NULL) {
dev_err (&udev->dev, "can't save CLEAR_TT_BUFFER state\n");
/* FIXME recover somehow ... RESET_TT? */
- return;
+ return -ENOMEM;
/* info that CLEAR_TT_BUFFER needs */
@@ -520,14 +527,19 @@ void usb_hub_tt_clear_buffer (struct usb_device *udev, int pipe)
if (usb_pipein (pipe))
clear->devinfo |= 1 << 15;
+ /* info for completion callback */
+ clear->hcd = bus_to_hcd(udev->bus);
+ clear->ep = urb->ep;
/* tell keventd to clear state for this TT */
spin_lock_irqsave (&tt->lock, flags);
list_add_tail (&clear->clear_list, &tt->clear_list);
- schedule_work (&tt->kevent);
+ schedule_work(&tt->clear_work);
spin_unlock_irqrestore (&tt->lock, flags);
+ return 0;
/* If do_delay is false, return the number of milliseconds the caller
* needs to delay.
@@ -818,7 +830,7 @@ static void hub_quiesce(struct usb_hub *hub, enum hub_quiescing_type type)
if (hub->has_indicators)
if (hub->tt.hub)
- cancel_work_sync(&hub->tt.kevent);
+ cancel_work_sync(&hub->tt.clear_work);
/* caller has locked the hub device */
@@ -935,7 +947,7 @@ static int hub_configure(struct usb_hub *hub,
spin_lock_init (&hub->tt.lock);
INIT_LIST_HEAD (&hub->tt.clear_list);
- INIT_WORK (&hub->tt.kevent, hub_tt_kevent);
+ INIT_WORK(&hub->tt.clear_work, hub_tt_work);
switch (hdev->descriptor.bDeviceProtocol) {
case 0: