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Diffstat (limited to 'drivers/char/hvc_console.c')
-rw-r--r--drivers/char/hvc_console.c31
1 files changed, 25 insertions, 6 deletions
diff --git a/drivers/char/hvc_console.c b/drivers/char/hvc_console.c
index a0a88aa23f5b..fc9bc7709fd9 100644
--- a/drivers/char/hvc_console.c
+++ b/drivers/char/hvc_console.c
@@ -47,8 +47,6 @@
47#define HVC_MAJOR 229 47#define HVC_MAJOR 229
48#define HVC_MINOR 0 48#define HVC_MINOR 0
49 49
50#define TIMEOUT (10)
51
52/* 50/*
53 * Wait this long per iteration while trying to push buffered data to the 51 * Wait this long per iteration while trying to push buffered data to the
54 * hypervisor before allowing the tty to complete a close operation. 52 * hypervisor before allowing the tty to complete a close operation.
@@ -550,6 +548,18 @@ static int hvc_chars_in_buffer(struct tty_struct *tty)
550 return hp->n_outbuf; 548 return hp->n_outbuf;
551} 549}
552 550
551/*
552 * timeout will vary between the MIN and MAX values defined here. By default
553 * and during console activity we will use a default MIN_TIMEOUT of 10. When
554 * the console is idle, we increase the timeout value on each pass through
555 * msleep until we reach the max. This may be noticeable as a brief (average
556 * one second) delay on the console before the console responds to input when
557 * there has been no input for some time.
558 */
559#define MIN_TIMEOUT (10)
560#define MAX_TIMEOUT (2000)
561static u32 timeout = MIN_TIMEOUT;
562
553#define HVC_POLL_READ 0x00000001 563#define HVC_POLL_READ 0x00000001
554#define HVC_POLL_WRITE 0x00000002 564#define HVC_POLL_WRITE 0x00000002
555 565
@@ -642,9 +652,14 @@ static int hvc_poll(struct hvc_struct *hp)
642 bail: 652 bail:
643 spin_unlock_irqrestore(&hp->lock, flags); 653 spin_unlock_irqrestore(&hp->lock, flags);
644 654
645 if (read_total) 655 if (read_total) {
656 /* Activity is occurring, so reset the polling backoff value to
657 a minimum for performance. */
658 timeout = MIN_TIMEOUT;
659
646 tty_flip_buffer_push(tty); 660 tty_flip_buffer_push(tty);
647 661 }
662
648 return poll_mask; 663 return poll_mask;
649} 664}
650 665
@@ -688,8 +703,12 @@ int khvcd(void *unused)
688 if (!hvc_kicked) { 703 if (!hvc_kicked) {
689 if (poll_mask == 0) 704 if (poll_mask == 0)
690 schedule(); 705 schedule();
691 else 706 else {
692 msleep_interruptible(TIMEOUT); 707 if (timeout < MAX_TIMEOUT)
708 timeout += (timeout >> 6) + 1;
709
710 msleep_interruptible(timeout);
711 }
693 } 712 }
694 __set_current_state(TASK_RUNNING); 713 __set_current_state(TASK_RUNNING);
695 } while (!kthread_should_stop()); 714 } while (!kthread_should_stop());