Merge branch 'linux-2.6' into for-2.6.22

[sfrench/cifs-2.6.git] / drivers / char / hvc_console.c

diff --git a/drivers/char/hvc_console.c b/drivers/char/hvc_console.c
index cc2cd46bedc6ac6dac8dd7d256a3605c784128cf..0f9ed7b46a6df81bb1332b1a048a2c475028cb00 100644 (file)
--- a/drivers/char/hvc_console.c
+++ b/drivers/char/hvc_console.c
@@ -47,8 +47,6 @@
 #define HVC_MAJOR      229
 #define HVC_MINOR      0
 
-#define TIMEOUT                (10)
-
 /*
  * Wait this long per iteration while trying to push buffered data to the
  * hypervisor before allowing the tty to complete a close operation.
@@ -104,12 +102,12 @@ static DEFINE_SPINLOCK(hvc_structs_lock);
 /*
  * This value is used to assign a tty->index value to a hvc_struct based
  * upon order of exposure via hvc_probe(), when we can not match it to
- * a console canidate registered with hvc_instantiate().
+ * a console candidate registered with hvc_instantiate().
  */
 static int last_hvc = -1;
 
 /*
- * Do not call this function with either the hvc_strucst_lock or the hvc_struct
+ * Do not call this function with either the hvc_structs_lock or the hvc_struct
  * lock held.  If successful, this function increments the kobject reference
  * count against the target hvc_struct so it should be released when finished.
  */
@@ -162,7 +160,7 @@ void hvc_console_print(struct console *co, const char *b, unsigned count)
        if (index >= MAX_NR_HVC_CONSOLES)
                return;
 
-       /* This console adapter was removed so it is not useable. */
+       /* This console adapter was removed so it is not usable. */
        if (vtermnos[index] < 0)
                return;
 
@@ -220,7 +218,7 @@ struct console hvc_con_driver = {
 };
 
 /*
- * Early console initialization.  Preceeds driver initialization.
+ * Early console initialization.  Precedes driver initialization.
  *
  * (1) we are first, and the user specified another driver
  * -- index will remain -1
@@ -257,7 +255,7 @@ int hvc_instantiate(uint32_t vtermno, int index, struct hv_ops *ops)
        if (vtermnos[index] != -1)
                return -1;
 
-       /* make sure no no tty has been registerd in this index */
+       /* make sure no no tty has been registered in this index */
        hp = hvc_get_by_index(index);
        if (hp) {
                kobject_put(&hp->kobj);
@@ -267,7 +265,7 @@ int hvc_instantiate(uint32_t vtermno, int index, struct hv_ops *ops)
        vtermnos[index] = vtermno;
        cons_ops[index] = ops;
 
-       /* reserve all indices upto and including this index */
+       /* reserve all indices up to and including this index */
        if (last_hvc < index)
                last_hvc = index;
 
@@ -316,7 +314,7 @@ static int hvc_open(struct tty_struct *tty, struct file * filp)
 {
        struct hvc_struct *hp;
        unsigned long flags;
-       int irq = NO_IRQ;
+       int irq = 0;
        int rc = 0;
        struct kobject *kobjp;
 
@@ -338,14 +336,14 @@ static int hvc_open(struct tty_struct *tty, struct file * filp)
        hp->tty = tty;
        /* Save for request_irq outside of spin_lock. */
        irq = hp->irq;
-       if (irq != NO_IRQ)
+       if (irq)
                hp->irq_requested = 1;
 
        kobjp = &hp->kobj;
 
        spin_unlock_irqrestore(&hp->lock, flags);
        /* check error, fallback to non-irq */
-       if (irq != NO_IRQ)
+       if (irq)
                rc = request_irq(irq, hvc_handle_interrupt, IRQF_DISABLED, "hvc_console", hp);
 
        /*
@@ -373,7 +371,7 @@ static void hvc_close(struct tty_struct *tty, struct file * filp)
 {
        struct hvc_struct *hp;
        struct kobject *kobjp;
-       int irq = NO_IRQ;
+       int irq = 0;
        unsigned long flags;
 
        if (tty_hung_up_p(filp))
@@ -407,7 +405,7 @@ static void hvc_close(struct tty_struct *tty, struct file * filp)
                 */
                tty_wait_until_sent(tty, HVC_CLOSE_WAIT);
 
-               if (irq != NO_IRQ)
+               if (irq)
                        free_irq(irq, hp);
 
        } else {
@@ -424,7 +422,7 @@ static void hvc_hangup(struct tty_struct *tty)
 {
        struct hvc_struct *hp = tty->driver_data;
        unsigned long flags;
-       int irq = NO_IRQ;
+       int irq = 0;
        int temp_open_count;
        struct kobject *kobjp;
 
@@ -453,7 +451,7 @@ static void hvc_hangup(struct tty_struct *tty)
                irq = hp->irq;
        hp->irq_requested = 0;
        spin_unlock_irqrestore(&hp->lock, flags);
-       if (irq != NO_IRQ)
+       if (irq)
                free_irq(irq, hp);
        while(temp_open_count) {
                --temp_open_count;
@@ -528,7 +526,7 @@ static int hvc_write(struct tty_struct *tty, const unsigned char *buf, int count
 
 /*
  * This is actually a contract between the driver and the tty layer outlining
- * how much write room the driver can guarentee will be sent OR BUFFERED.  This
+ * how much write room the driver can guarantee will be sent OR BUFFERED.  This
  * driver MUST honor the return value.
  */
 static int hvc_write_room(struct tty_struct *tty)
@@ -550,6 +548,18 @@ static int hvc_chars_in_buffer(struct tty_struct *tty)
        return hp->n_outbuf;
 }
 
+/*
+ * timeout will vary between the MIN and MAX values defined here.  By default
+ * and during console activity we will use a default MIN_TIMEOUT of 10.  When
+ * the console is idle, we increase the timeout value on each pass through
+ * msleep until we reach the max.  This may be noticeable as a brief (average
+ * one second) delay on the console before the console responds to input when
+ * there has been no input for some time.
+ */
+#define MIN_TIMEOUT            (10)
+#define MAX_TIMEOUT            (2000)
+static u32 timeout = MIN_TIMEOUT;
+
 #define HVC_POLL_READ  0x00000001
 #define HVC_POLL_WRITE 0x00000002
 
@@ -583,7 +593,7 @@ static int hvc_poll(struct hvc_struct *hp)
        /* If we aren't interrupt driven and aren't throttled, we always
         * request a reschedule
         */
-       if (hp->irq == NO_IRQ)
+       if (hp->irq == 0)
                poll_mask |= HVC_POLL_READ;
 
        /* Read data if any */
@@ -642,9 +652,14 @@ static int hvc_poll(struct hvc_struct *hp)
  bail:
        spin_unlock_irqrestore(&hp->lock, flags);
 
-       if (read_total)
+       if (read_total) {
+               /* Activity is occurring, so reset the polling backoff value to
+                  a minimum for performance. */
+               timeout = MIN_TIMEOUT;
+
                tty_flip_buffer_push(tty);
-       
+       }
+
        return poll_mask;
 }
 
@@ -688,8 +703,12 @@ int khvcd(void *unused)
                if (!hvc_kicked) {
                        if (poll_mask == 0)
                                schedule();
-                       else
-                               msleep_interruptible(TIMEOUT);
+                       else {
+                               if (timeout < MAX_TIMEOUT)
+                                       timeout += (timeout >> 6) + 1;
+
+                               msleep_interruptible(timeout);
+                       }
                }
                __set_current_state(TASK_RUNNING);
        } while (!kthread_should_stop());
@@ -794,7 +813,7 @@ int __devexit hvc_remove(struct hvc_struct *hp)
 
        /*
         * We 'put' the instance that was grabbed when the kobject instance
-        * was intialized using kobject_init().  Let the last holder of this
+        * was initialized using kobject_init().  Let the last holder of this
         * kobject cause it to be removed, which will probably be the tty_hangup
         * below.
         */
@@ -850,7 +869,7 @@ int __init hvc_init(void)
 }
 module_init(hvc_init);
 
-/* This isn't particularily necessary due to this being a console driver
+/* This isn't particularly necessary due to this being a console driver
  * but it is nice to be thorough.
  */
 static void __exit hvc_exit(void)