Re: [PATCH] Use tty_schedule in VT code.

James Simmons
2007-07-18T19:57:58Z

> While I have no problem with this, it would be a significant
> behavior change (more so than changing the initial delay to 0).
>
> IIRC, when the serial_core dead lock was being debugged
> (by Russel King with some Dell guy who reported it 1-2 years ago)
> this change was suggested and rejected because some callers
> are not running at IRQ context and want to use low_latency.
> In the end, I think they decided to leave the correct use of
> low_latency WRT running in IRQ context to the caller.
>
> It might be safest to drop this portion so you can get the
> obvious part of the patch accepted (consolidating
> the redundant xxx_schedule_flip functions).

Done. I still smell a dead lock issue tho.

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/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