Re: patch usb-add-usb_autopm_get_interface_burst.patch added to gregkh-2.6 tree

On Tue, 10 Jul 2007 [email protected] wrote:

> This is a note to let you know that I've just added the patch titled
> 
>      Subject: USB: add usb_autopm_get_interface_burst()
> 
> to my gregkh-2.6 tree.  Its filename is
> 
>      usb-add-usb_autopm_get_interface_burst.patch
> 
> This tree can be found at 
>     http://www.kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/patches/
> 
> 
> >From [email protected] Fri Jul  6 11:21:32 2007
> From: Alan Stern <[email protected]>
> Date: Fri, 6 Jul 2007 14:21:26 -0400 (EDT)
> Subject: USB: add usb_autopm_get_interface_burst()
> To: Greg KH <[email protected]>
> Cc: USB development list <[email protected]>
> Message-ID: <[email protected]>
> 
> 
> This patch (as929) adds usb_autopm_get_interface_burst() to the
> autosuspend programming interface.  It is intended for situations
> where I/O events occur in bursts of activity; it reduces overhead by
> not cancelling the device's autosuspend timer.

Ironically, I just got a message from Thomas Gleixner indicating this
patch is unnecessary.  My own tests confirm his conclusion; there was
no measurable difference in CPU utilization when reading a flash
storage device with or without the burst-mode suspend routine.

So I would like to withdraw this patch.  The following
usb-storage-implement-autosuspend.patch (as930) will then need the
adjustment below (it can easily be merged into that patch).

Sorry for the extra trouble,

Alan Stern



Index: usb-2.6/drivers/usb/storage/usb.c
===================================================================
--- usb-2.6.orig/drivers/usb/storage/usb.c
+++ usb-2.6/drivers/usb/storage/usb.c
@@ -321,7 +321,7 @@ static int usb_stor_control_thread(void 
 		US_DEBUGP("*** thread awakened.\n");
 
 		/* Autoresume the device */
-		autopm_rc = usb_autopm_get_interface_burst(us->pusb_intf);
+		autopm_rc = usb_autopm_get_interface(us->pusb_intf);
 
 		/* lock the device pointers */
 		mutex_lock(&(us->dev_mutex));




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