diff options
Diffstat (limited to 'debian/patches-rt/0165-tty-serial-pl011-Make-the-locking-work-on-RT.patch')
| -rw-r--r-- | debian/patches-rt/0165-tty-serial-pl011-Make-the-locking-work-on-RT.patch | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/debian/patches-rt/0165-tty-serial-pl011-Make-the-locking-work-on-RT.patch b/debian/patches-rt/0165-tty-serial-pl011-Make-the-locking-work-on-RT.patch new file mode 100644 index 000000000..6309f7e50 --- /dev/null +++ b/debian/patches-rt/0165-tty-serial-pl011-Make-the-locking-work-on-RT.patch @@ -0,0 +1,54 @@ +From e699af6cca35d036a6876b5c9ec0b1355cc16842 Mon Sep 17 00:00:00 2001 +From: Thomas Gleixner <tglx@linutronix.de> +Date: Tue, 8 Jan 2013 21:36:51 +0100 +Subject: [PATCH 165/347] tty/serial/pl011: Make the locking work on RT +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz + +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(-) + +diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c +index 5edc3813a9b9..7d4aee4c5091 100644 +--- a/drivers/tty/serial/amba-pl011.c ++++ b/drivers/tty/serial/amba-pl011.c +@@ -2196,13 +2196,19 @@ pl011_console_write(struct console *co, const char *s, unsigned int count) + + 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 +@@ -2228,8 +2234,7 @@ pl011_console_write(struct console *co, const char *s, unsigned int count) + 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); + } +-- +2.36.1 + |