Re: [PATCH] Use tty_schedule in VT code.

James Simmons
2007-07-18T18:18:13Z

> > What should be done is
> >
> > if (tty->low_latency)
> > flush_to_ldisc(&tty->buf.work.work);
> > else
> > schedule_delayed_work(&tty->buf.work, 1);
> >
> > Is this acceptable to you?
>
> In that case, we might as well just always do the scheduled_delayed_work()
> with a zero timeout as per the earlier patch. I'd still like to know who
> *cares*, though? Why not leave it at 1?

I have no problem leaving at one. Here is the new patch. I did address the
problem with tty_flip_buffer_push in this patch. It is possible for a
driver to call tty_flip_buffer_push within a interrupt context if they
set the low_latency flag.

diff --git a/drivers/char/keyboard.c b/drivers/char/keyboard.c
index 2ce0af1..68eab40 100644
--- a/drivers/char/keyboard.c
+++ b/drivers/char/keyboard.c
@@ -278,7 +278,7 @@ static void put_queue(struct vc_data *vc, int ch)

if (tty) {
tty_insert_flip_char(tty, ch, 0);
- con_schedule_flip(tty);
+ tty_schedule_flip(tty);
}
}

@@ -293,7 +293,7 @@ static void puts_queue(struct vc_data *vc, char *cp)
tty_insert_flip_char(tty, *cp, 0);
cp++;
}
- con_schedule_flip(tty);
+ tty_schedule_flip(tty);
}

static void applkey(struct vc_data *vc, int key, char mode)
@@ -533,7 +533,7 @@ static void fn_send_intr(struct vc_data *vc)
if (!tty)
return;
tty_insert_flip_char(tty, 0, TTY_BREAK);
- con_schedule_flip(tty);
+ tty_schedule_flip(tty);
}

static void fn_scroll_forw(struct vc_data *vc)
diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index de37ebc..8533173 100644
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -3647,11 +3647,7 @@ void tty_flip_buffer_push(struct tty_struct *tty)
if (tty->buf.tail != NULL)
tty->buf.tail->commit = tty->buf.tail->used;
spin_unlock_irqrestore(&tty->buf.lock, flags);
-
- if (tty->low_latency)
- flush_to_ldisc(&tty->buf.work.work);
- else
- schedule_delayed_work(&tty->buf.work, 1);
+ schedule_delayed_work(&tty->buf.work, 1);
}

EXPORT_SYMBOL(tty_flip_buffer_push);
diff --git a/drivers/char/vt.c b/drivers/char/vt.c
index edb7002..d17cfcd 100644
--- a/drivers/char/vt.c
+++ b/drivers/char/vt.c
@@ -1260,7 +1260,7 @@ static void respond_string(const char *p, struct tty_struct *tty)
tty_insert_flip_char(tty, *p, 0);
p++;
}
- con_schedule_flip(tty);
+ tty_schedule_flip(tty);
}

static void cursor_report(struct vc_data *vc, struct tty_struct *tty)
diff --git a/include/linux/kbd_kern.h b/include/linux/kbd_kern.h
index 506ad20..7b24a0d 100644
--- a/include/linux/kbd_kern.h
+++ b/include/linux/kbd_kern.h
@@ -149,16 +149,4 @@ void compute_shiftstate(void);

extern unsigned int keymap_count;

-/* console.c */
-
-static inline void con_schedule_flip(struct tty_struct *t)
-{
- unsigned long flags;
- spin_lock_irqsave(&t->buf.lock, flags);
- if (t->buf.tail != NULL)
- t->buf.tail->commit = t->buf.tail->used;
- spin_unlock_irqrestore(&t->buf.lock, flags);
- schedule_delayed_work(&t->buf.work, 0);
-}
-
#endif