Re: [PATCH 12/18] serial: sifive: Use uart_prepare_sysrq_char() to handle sysrq.

From: Samuel Holland <samuel.holland@sifive.com>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	linux-serial@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jiri Slaby <jirislaby@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	linux-riscv@lists.infradead.org
Subject: Re: [PATCH 12/18] serial: sifive: Use uart_prepare_sysrq_char() to handle sysrq.
Date: Wed, 6 Mar 2024 19:39:19 -0600	[thread overview]
Message-ID: <ddf63d8b-7818-4c25-a83a-255ea45ea027@sifive.com> (raw)
In-Reply-To: <20240301215246.891055-13-bigeasy@linutronix.de>

On 2024-03-01 3:45 PM, Sebastian Andrzej Siewior wrote:
> The port lock is a spinlock_t which is becomes a sleeping lock on PREEMPT_RT.
> The driver splits the locking function into two parts: local_irq_save() and
> uart_port_lock() and this breaks PREEMPT_RT.
> 
> Handle sysrq requests sysrq once the port lock is dropped.
> Remove the special case in the console write routine an always use the
> complete locking function.
> 
> Cc: Palmer Dabbelt <palmer@dabbelt.com>
> Cc: Paul Walmsley <paul.walmsley@sifive.com>
> Cc: linux-riscv@lists.infradead.org
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> ---
>  drivers/tty/serial/sifive.c | 17 +++++++----------
>  1 file changed, 7 insertions(+), 10 deletions(-)

Acked-by: Samuel Holland <samuel.holland@sifive.com>
Tested-by: Samuel Holland <samuel.holland@sifive.com>