[patch]autosuspend for usb storage

Hi,

this patch implements autosuspend for usb-storage.
The device may autosuspend except while
1. a scsi request is being processed
2. a bus is scanned for devices
3. a scsi reset is in progress

	Regards
		Oliver
Signed-off-by: Oliver Neukum <[email protected]>
-- 

--- linux-2.6.21-rc7/drivers/usb/storage/scsiglue.c	2007-04-25 08:48:23.000000000 +0200
+++ linux-2.6.21-rc7-auto/drivers/usb/storage/scsiglue.c	2007-04-25 08:56:08.000000000 +0200
@@ -287,7 +287,11 @@ static int device_reset(struct scsi_cmnd
 
 	/* lock the device pointers and do the reset */
 	mutex_lock(&(us->dev_mutex));
-	result = us->transport_reset(us);
+	result = usb_autopm_get_interface(us->pusb_intf);
+	if (!result) {
+		result = us->transport_reset(us);
+		usb_autopm_put_interface(us->pusb_intf);
+	}
 	mutex_unlock(&us->dev_mutex);
 
 	return result < 0 ? FAILED : SUCCESS;
--- linux-2.6.21-rc7/drivers/usb/storage/usb.c	2007-04-25 08:48:23.000000000 +0200
+++ linux-2.6.21-rc7-auto/drivers/usb/storage/usb.c	2007-04-24 14:03:56.000000000 +0200
@@ -68,6 +68,8 @@
 #include "debug.h"
 #include "initializers.h"
 
+#include "../core/usb.h"
+
 #ifdef CONFIG_USB_STORAGE_USBAT
 #include "shuttle_usbat.h"
 #endif
@@ -190,19 +192,19 @@ static struct us_unusual_dev us_unusual_
 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);
 	iface->dev.power.power_state.event = message.event;
 
 	/* 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;
 }
 
@@ -210,14 +212,12 @@ static int storage_resume(struct usb_int
 {
 	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);
 	iface->dev.power.power_state.event = PM_EVENT_ON;
 
-	mutex_unlock(&us->dev_mutex);
 	return 0;
 }
 
@@ -300,6 +300,7 @@ static int usb_stor_control_thread(void 
 {
 	struct us_data *us = (struct us_data *)__us;
 	struct Scsi_Host *host = us_to_host(us);
+	int res;
 
 	current->flags |= PF_NOFREEZE;
 
@@ -311,6 +312,7 @@ static int usb_stor_control_thread(void 
 		US_DEBUGP("*** thread awakened.\n");
 
 		/* lock the device pointers */
+		usb_pm_lock(us->pusb_dev);
 		mutex_lock(&(us->dev_mutex));
 
 		/* if the device has disconnected, we are free to exit */
@@ -370,8 +372,15 @@ static int usb_stor_control_thread(void 
 
 		/* we've got a command, let's do it! */
 		else {
-			US_DEBUG(usb_stor_show_command(us->srb));
-			us->proto_handler(us->srb, us);
+			res = __usb_autopm_do_interface(us->pusb_intf, 1);
+			if (!res) {
+				US_DEBUG(usb_stor_show_command(us->srb));
+				us->proto_handler(us->srb, us);
+				__usb_autopm_do_interface(us->pusb_intf, -1);
+			} else {
+				us->srb->result = DID_ERROR << 16;
+				US_DEBUGP("Could not wake device\n");
+			}
 		}
 
 		/* lock access to the state */
@@ -410,6 +419,7 @@ SkipForAbort:
 
 		/* unlock the device pointers */
 		mutex_unlock(&us->dev_mutex);
+		usb_pm_unlock(us->pusb_dev);
 	} /* for (;;) */
 
 	scsi_host_put(host);
@@ -938,6 +948,7 @@ retry:
 	}
 
 	scsi_host_put(us_to_host(us));
+	usb_autopm_put_interface(us->pusb_intf);
 	complete_and_exit(&threads_gone, 0);
 }
 
@@ -1027,6 +1038,7 @@ static int storage_probe(struct usb_inte
 	 * 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;
@@ -1063,6 +1075,7 @@ static struct usb_driver usb_storage_dri
 	.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)

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