USB: additional power savings for cdc-acm devices that support remote wakeup

this patch saves power for cdc-acm devices that support remote wakeup
while the device is connected.

- request needs_remote_wakeup when needed
- delayed write while a device is autoresumed
- the device is marked busy when appropriate

Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/usb/class/cdc-acm.h b/drivers/usb/class/cdc-acm.h
index 046e064b033a..85c3aaaab7c5 100644
--- a/drivers/usb/class/cdc-acm.h
+++ b/drivers/usb/class/cdc-acm.h
@@ -107,10 +107,14 @@ struct acm {
         struct list_head filled_read_bufs;
         int write_used;                                 /* number of non-empty write buffers */
         int write_ready;                                /* write urb is not running */
+        int old_ready;
+        int processing;
+        int transmitting;
         spinlock_t write_lock;
         struct mutex mutex;
         struct usb_cdc_line_coding line;                /* bits, stop, parity */
         struct work_struct work;                        /* work queue entry for line discipline waking up */
+        struct work_struct waker;
         struct tasklet_struct urb_task;                 /* rx processing */
         spinlock_t throttle_lock;                       /* synchronize throtteling and read callback */
         unsigned int ctrlin;                            /* input control lines (DCD, DSR, RI, break, overruns) */
@@ -123,6 +127,7 @@ struct acm {
         unsigned char clocal;                           /* termios CLOCAL */
         unsigned int ctrl_caps;                         /* control capabilities from the class specific header */
         unsigned int susp_count;                        /* number of suspended interfaces */
+        struct acm_wb *delayed_wb;                      /* write queued for a device about to be woken */
 };
 
 #define CDC_DATA_INTERFACE_TYPE 0x0a