diff options
Diffstat (limited to 'drivers/char/hvc_console.c')
| -rw-r--r-- | drivers/char/hvc_console.c | 49 |
1 files changed, 34 insertions, 15 deletions
diff --git a/drivers/char/hvc_console.c b/drivers/char/hvc_console.c index a0a88aa23f5..0f9ed7b46a6 100644 --- 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; @@ -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 @@ -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) |