Messages in this thread Patch in this message | | | Date | Tue, 08 May 2007 09:53:05 -0400 | From | Mark Lord <> | Subject | Re: [BUG] usb/core/hub.c loops forever on resume from ram due to bluetooth |
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Greg ?
The oddball thing here is that on a UP machine with a UP kernel, this (below) was never an issue.
After moving the drive to a dual-core machine and rebuilding the kernel with SMP=y, the problem becomes a killer here. The two machines are nearly identical, apart from the CPUs.
The failing machine is a Dell Inspiron 9400, and mine isn't the only unit that has this issue.
----------Original message:
I have just replaced my primary single-core notebook with a nearly identical dual-core notebook, and moved the usb-bluetooth peripheral from the old machine to the new one.
On the single-core machine, suspend/resume (RAM) worked fine even with the bluetooth module enabled.
On the new dual-core machine, resuming with bluetooth enabled results in an infinite(?) lockup in an unbounded loop in hub_tt_kevent(). With PM debug on, I see tens of thousands of these messages scrolling on the console:
kernel: usb 5-1: clear tt 4 (9042) error -71 kernel: usb 5-1: clear tt 4 (9042) error -71 kernel: usb 5-1: clear tt 4 (9042) error -71 (over and over and ...)
By restricting iterations on the unbounded loop the machine is able to resume again.
Greg / Marcel: any words of wisdom?
And we should probably put bounds permanently on that loop:
I devised/used this patch to accomplish it. Now, I still get close to a thousand or so such messages, in groups, showing up in syslog, but at least the system can resume after suspend.
Signed-off-by: Mark Lord <mlord@pobox.com>
--- linux/drivers/usb/core/hub.c.orig 2007-04-26 12:02:47.000000000 -0400 +++ linux/drivers/usb/core/hub.c 2007-05-01 18:48:46.000000000 -0400 @@ -403,9 +403,10 @@ struct usb_hub *hub = container_of(work, struct usb_hub, tt.kevent); unsigned long flags; + int limit = 500;
spin_lock_irqsave (&hub->tt.lock, flags); - while (!list_empty (&hub->tt.clear_list)) { + while (--limit && !list_empty (&hub->tt.clear_list)) { struct list_head *temp; struct usb_tt_clear *clear; struct usb_device *hdev = hub->hdev; ----- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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