On Mon, Jul 16, 2007 at 10:38:48AM -0400, Alan Stern wrote:
> > -static int usb_autosuspend_delay = 2; /* Default delay value,
> > +static int usb_autosuspend_delay = 0; /* Default delay value,
> > * in seconds */
> > module_param_named(autosuspend, usb_autosuspend_delay, int, 0644);
> > MODULE_PARM_DESC(autosuspend, "default autosuspend delay");
>
> Ooh! Don't do that. Starting in 2.6.22, setting the delay to 0 means
> "autosuspend as soon as possible". (It was different in 2.6.21.) The
> variable now needs to be set to -1 to prevent autosuspending.
Ah, missed that. Thanks.
> > in usb_autopm_do_device()
> > I'm suspecting logic is underflowing here causing this.
>
> Yes, that's what it means. I'm puzzled as to how this could occur; let
> me try some tests. What types of devices give rise to these warnings?
On the machine I tried it on, there's nothing really exotic..
lsusb shows..
Bus 005 Device 054: ID 0781:5150 SanDisk Corp. SDCZ2 Cruzer Mini Flash Drive
(thin)
Bus 005 Device 002: ID 050d:0234 Belkin Components F5U234 USB 2.0 4-Port Hub
Bus 005 Device 001: ID 0000:0000
Bus 004 Device 003: ID 0aec:3050 Neodio Technologies Corp. ND3050 8-in-1 Card
Reader
Bus 004 Device 001: ID 0000:0000
Bus 003 Device 001: ID 0000:0000
Bus 002 Device 004: ID 04a9:1097 Canon, Inc.
Bus 002 Device 003: ID 045e:0053 Microsoft Corp.
Bus 002 Device 001: ID 0000:0000
Bus 001 Device 001: ID 0000:0000
so, usb memory stick, hub, card reader, printer, mouse.
The 28 warnings in my dmesg are all preceded by..
usb 5-1.4: new high speed USB device using ehci_hcd and address 51
usb 5-1.4: configuration #1 chosen from 1 choice
I'm not sure how that 5-1.4 relates to the above map.
oh, there's one other case, where it prints the same thing for usb 4-2:
> The differences between setting usb_autosuspend_delay to -1 and turning
> off CONFIG_USB_SUSPEND:
>
> Setting the default delay to -1 allows users to enable
> autosuspend on a per-device basis. For that matter, you
> might want to add a line to the hub driver, to enable
> autosuspend for hubs by default.
>
> It adds more code to the kernel (obviously).
>
> It changes the way suspend-to-RAM behaves: individual USB
> devices get suspended as opposed to suspending an entire
> bus all at once. In theory this shouldn't matter.
>
> I can't think of anything else at the moment.
Ok, thanks for the info.
Dave
--
http://www.codemonkey.org.uk
-------------------------------------------------------------------------
This SF.net email is sponsored by DB2 Express
Download DB2 Express C - the FREE version of DB2 express and take
control of your XML. No limits. Just data. Click to get it now.
http://sourceforge.net/powerbar/db2/
_______________________________________________
linux-usb-devel@lists.sourceforge.net
To unsubscribe, use the last form field at:
https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
