USB: autosuspend for usblcd
this patch implements autosuspend for the usblcd driver. It uses
the new usb_anchor infrastructure. Many thanks to Georges for testing.
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Cc: Georges Toth <g.toth@e-biz.lu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/misc/usblcd.c b/drivers/usb/misc/usblcd.c
index 6e093c2..504f722 100644
--- a/drivers/usb/misc/usblcd.c
+++ b/drivers/usb/misc/usblcd.c
@@ -45,6 +45,7 @@
struct kref kref;
struct semaphore limit_sem; /* to stop writes at full throttle from
* using up all RAM */
+ struct usb_anchor submitted; /* URBs to wait for before suspend */
};
#define to_lcd_dev(d) container_of(d, struct usb_lcd, kref)
@@ -67,7 +68,7 @@
{
struct usb_lcd *dev;
struct usb_interface *interface;
- int subminor;
+ int subminor, r;
subminor = iminor(inode);
@@ -85,6 +86,13 @@
/* increment our usage count for the device */
kref_get(&dev->kref);
+ /* grab a power reference */
+ r = usb_autopm_get_interface(interface);
+ if (r < 0) {
+ kref_put(&dev->kref, lcd_delete);
+ return r;
+ }
+
/* save our object in the file's private structure */
file->private_data = dev;
@@ -100,6 +108,7 @@
return -ENODEV;
/* decrement the count on our device */
+ usb_autopm_put_interface(dev->interface);
kref_put(&dev->kref, lcd_delete);
return 0;
}
@@ -225,12 +234,14 @@
usb_sndbulkpipe(dev->udev, dev->bulk_out_endpointAddr),
buf, count, lcd_write_bulk_callback, dev);
urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+
+ usb_anchor_urb(urb, &dev->submitted);
/* send the data out the bulk port */
retval = usb_submit_urb(urb, GFP_KERNEL);
if (retval) {
err("USBLCD: %s - failed submitting write urb, error %d", __FUNCTION__, retval);
- goto error;
+ goto error_unanchor;
}
/* release our reference to this urb, the USB core will eventually free it entirely */
@@ -238,7 +249,8 @@
exit:
return count;
-
+error_unanchor:
+ usb_unanchor_urb(urb);
error:
usb_buffer_free(dev->udev, count, buf, urb->transfer_dma);
usb_free_urb(urb);
@@ -283,6 +295,7 @@
}
kref_init(&dev->kref);
sema_init(&dev->limit_sem, USB_LCD_CONCURRENT_WRITES);
+ init_usb_anchor(&dev->submitted);
dev->udev = usb_get_dev(interface_to_usbdev(interface));
dev->interface = interface;
@@ -350,6 +363,30 @@
return retval;
}
+static void lcd_draw_down(struct usb_lcd *dev)
+{
+ int time;
+
+ time = usb_wait_anchor_empty_timeout(&dev->submitted, 1000);
+ if (!time)
+ usb_kill_anchored_urbs(&dev->submitted);
+}
+
+static int lcd_suspend(struct usb_interface *intf, pm_message_t message)
+{
+ struct usb_lcd *dev = usb_get_intfdata(intf);
+
+ if (!dev)
+ return 0;
+ lcd_draw_down(dev);
+ return 0;
+}
+
+static int lcd_resume (struct usb_interface *intf)
+{
+ return 0;
+}
+
static void lcd_disconnect(struct usb_interface *interface)
{
struct usb_lcd *dev;
@@ -371,7 +408,10 @@
.name = "usblcd",
.probe = lcd_probe,
.disconnect = lcd_disconnect,
+ .suspend = lcd_suspend,
+ .resume = lcd_resume,
.id_table = id_table,
+ .supports_autosuspend = 1,
};
static int __init usb_lcd_init(void)