| Subject: tty/serial/pl011: Make the locking work on RT |
| From: Thomas Gleixner <tglx@linutronix.de> |
| Date: Tue, 08 Jan 2013 21:36:51 +0100 |
| |
| The lock is a sleeping lock and local_irq_save() is not the optimsation |
| we are looking for. Redo it to make it work on -RT and non-RT. |
| |
| Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
| --- |
| drivers/tty/serial/amba-pl011.c | 15 ++++++++++----- |
| 1 file changed, 10 insertions(+), 5 deletions(-) |
| |
| --- a/drivers/tty/serial/amba-pl011.c |
| +++ b/drivers/tty/serial/amba-pl011.c |
| @@ -2166,13 +2166,19 @@ pl011_console_write(struct console *co, |
| |
| clk_enable(uap->clk); |
| |
| - local_irq_save(flags); |
| + /* |
| + * local_irq_save(flags); |
| + * |
| + * This local_irq_save() is nonsense. If we come in via sysrq |
| + * handling then interrupts are already disabled. Aside of |
| + * that the port.sysrq check is racy on SMP regardless. |
| + */ |
| if (uap->port.sysrq) |
| locked = 0; |
| else if (oops_in_progress) |
| - locked = spin_trylock(&uap->port.lock); |
| + locked = spin_trylock_irqsave(&uap->port.lock, flags); |
| else |
| - spin_lock(&uap->port.lock); |
| + spin_lock_irqsave(&uap->port.lock, flags); |
| |
| /* |
| * First save the CR then disable the interrupts |
| @@ -2196,8 +2202,7 @@ pl011_console_write(struct console *co, |
| pl011_write(old_cr, uap, REG_CR); |
| |
| if (locked) |
| - spin_unlock(&uap->port.lock); |
| - local_irq_restore(flags); |
| + spin_unlock_irqrestore(&uap->port.lock, flags); |
| |
| clk_disable(uap->clk); |
| } |
