Input: Hold wake lock while event queue is not empty.

Allows userspace code to process input events while
the device appears to be asleep.

Signed-off-by: Arve Hjønnevåg <arve@android.com>

diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
index be0921ef6b52ace2a2e15a5d1437c6134799dbf0..1f571d73d9f2f2281992a4455893f0c8a08ee077 100644 (file)
--- a/drivers/input/evdev.c
+++ b/drivers/input/evdev.c
@@ -23,6 +23,7 @@
 #include <linux/input.h>
 #include <linux/major.h>
 #include <linux/device.h>
+#include <linux/wakelock.h>
 #include "input-compat.h"
 
 struct evdev {
@@ -43,6 +44,7 @@ struct evdev_client {
        unsigned int tail;
        unsigned int packet_head; /* [future] position of the first element of next packet */
        spinlock_t buffer_lock; /* protects access to buffer, head and tail */
+       struct wake_lock wake_lock;
        struct fasync_struct *fasync;
        struct evdev *evdev;
        struct list_head node;
@@ -59,6 +61,7 @@ static void evdev_pass_event(struct evdev_client *client,
        /* Interrupts are disabled, just acquire the lock. */
        spin_lock(&client->buffer_lock);
 
+       wake_lock_timeout(&client->wake_lock, 5 * HZ);
        client->buffer[client->head++] = *event;
        client->head &= client->bufsize - 1;
 
@@ -254,6 +257,7 @@ static int evdev_release(struct inode *inode, struct file *file)
        mutex_unlock(&evdev->mutex);
 
        evdev_detach_client(evdev, client);
+       wake_lock_destroy(&client->wake_lock);
        kfree(client);
 
        evdev_close_device(evdev);
@@ -305,6 +309,7 @@ static int evdev_open(struct inode *inode, struct file *file)
 
        client->bufsize = bufsize;
        spin_lock_init(&client->buffer_lock);
+       wake_lock_init(&client->wake_lock, WAKE_LOCK_SUSPEND, "evdev");
        client->evdev = evdev;
        evdev_attach_client(evdev, client);
 
@@ -372,6 +377,8 @@ static int evdev_fetch_next_event(struct evdev_client *client,
        if (have_event) {
                *event = client->buffer[client->tail++];
                client->tail &= client->bufsize - 1;
+               if (client->head == client->tail)
+                       wake_unlock(&client->wake_lock);
        }
 
        spin_unlock_irq(&client->buffer_lock);