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Commit 8dfe4b14 authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman
Browse files

usb-storage: implement autosuspend 



This patch (as930) implements autosuspend for usb-storage.  It is
adapted from a patch by Oliver Neukum.  Autosuspend is allowed except
during LUN scanning, resets, and command execution.

Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent b0e2a705

drivers/usb/storage/scsiglue.c

+9 −4
Original line number Diff line number Diff line
@@ -285,10 +285,15 @@ static int device_reset(struct scsi_cmnd *srb) 


	US_DEBUGP("%s called\n", __FUNCTION__);



	result = usb_autopm_get_interface(us->pusb_intf);

	if (result == 0) {



		/* lock the device pointers and do the reset */

		mutex_lock(&(us->dev_mutex));

		result = us->transport_reset(us);

		mutex_unlock(&us->dev_mutex);

		usb_autopm_put_interface(us->pusb_intf);

	}



	return result < 0 ? FAILED : SUCCESS;

}

drivers/usb/storage/usb.c

+20 −7
Original line number Diff line number Diff line
@@ -191,16 +191,14 @@ static int storage_suspend(struct usb_interface *iface, pm_message_t message) 
{

	struct us_data *us = usb_get_intfdata(iface);



	US_DEBUGP("%s\n", __FUNCTION__);



	/* Wait until no command is running */

	mutex_lock(&us->dev_mutex);



	US_DEBUGP("%s\n", __FUNCTION__);

	if (us->suspend_resume_hook)

		(us->suspend_resume_hook)(us, US_SUSPEND);



	/* When runtime PM is working, we'll set a flag to indicate

	 * whether we should autoresume when a SCSI request arrives. */



	mutex_unlock(&us->dev_mutex);

	return 0;

}
@@ -209,13 +207,11 @@ static int storage_resume(struct usb_interface *iface) 
{

	struct us_data *us = usb_get_intfdata(iface);



	mutex_lock(&us->dev_mutex);



	US_DEBUGP("%s\n", __FUNCTION__);



	if (us->suspend_resume_hook)

		(us->suspend_resume_hook)(us, US_RESUME);



	mutex_unlock(&us->dev_mutex);

	return 0;

}
@@ -313,6 +309,7 @@ static int usb_stor_control_thread(void * __us) 
{

	struct us_data *us = (struct us_data *)__us;

	struct Scsi_Host *host = us_to_host(us);

	int autopm_rc;



	current->flags |= PF_NOFREEZE;
@@ -323,6 +320,9 @@ static int usb_stor_control_thread(void * __us) 
			

		US_DEBUGP("*** thread awakened.\n");



		/* Autoresume the device */

		autopm_rc = usb_autopm_get_interface(us->pusb_intf);



		/* lock the device pointers */

		mutex_lock(&(us->dev_mutex));
@@ -381,6 +381,12 @@ static int usb_stor_control_thread(void * __us) 
			us->srb->result = SAM_STAT_GOOD;

		}



		/* Did the autoresume fail? */

		else if (autopm_rc < 0) {

			US_DEBUGP("Could not wake device\n");

			us->srb->result = DID_ERROR << 16;

		}



		/* we've got a command, let's do it! */

		else {

			US_DEBUG(usb_stor_show_command(us->srb));
@@ -423,6 +429,10 @@ static int usb_stor_control_thread(void * __us) 


		/* unlock the device pointers */

		mutex_unlock(&us->dev_mutex);



		/* Start an autosuspend */

		if (autopm_rc == 0)

			usb_autopm_put_interface(us->pusb_intf);

	} /* for (;;) */



	/* Wait until we are told to stop */
@@ -939,6 +949,7 @@ static int usb_stor_scan_thread(void * __us) 
	}



	scsi_host_put(us_to_host(us));

	usb_autopm_put_interface(us->pusb_intf);

	complete_and_exit(&threads_gone, 0);

}
@@ -1028,6 +1039,7 @@ static int storage_probe(struct usb_interface *intf, 
	 * start it up. */

	scsi_host_get(us_to_host(us));

	atomic_inc(&total_threads);

	usb_autopm_get_interface(intf); /* dropped in the scanning thread */

	wake_up_process(th);



	return 0;
@@ -1065,6 +1077,7 @@ static struct usb_driver usb_storage_driver = { 
	.pre_reset =	storage_pre_reset,

	.post_reset =	storage_post_reset,

	.id_table =	storage_usb_ids,

	.supports_autosuspend = 1,

};



static int __init usb_stor_init(void)