From: Dmitry Safonov <dima@arista.com>
To: Joe Perches <joe@perches.com>, linux-kernel@vger.kernel.org
Cc: Dmitry Safonov <0x7f454c46@gmail.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jiri Slaby <jslaby@suse.com>,
Vasiliy Khoruzhick <vasilykh@arista.com>,
linux-serial@vger.kernel.org
Subject: Re: [PATCH-next 3/3] serial/sysrq: Add MAGIC_SYSRQ_SERIAL_SEQUENCE
Date: Fri, 10 Jan 2020 22:10:15 +0000 [thread overview]
Message-ID: <056bff50-f67e-f00f-c98f-ccb427344691@arista.com> (raw)
In-Reply-To: <5293a7cb1ccb16275ddb36c7f26fb9e83f4fac9b.camel@perches.com>
Hi Joe,
On 1/10/20 4:50 PM, Joe Perches wrote:
> On Thu, 2020-01-09 at 21:54 +0000, Dmitry Safonov wrote:
>> Many embedded boards have a disconnected TTL level serial which can
>> generate some garbage that can lead to spurious false sysrq detects.
>
> trivia:
>
>> diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
> []
>> @@ -3081,6 +3081,38 @@ void uart_insert_char(struct uart_port *port, unsigned int status,
> []
>> +const char sysrq_toggle_seq[] = CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE;
>
> static const?
Will do, thanks!
>
>> +static int uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch)
>
> This function return might read better as bool not int
Yeah, no hard feelings, will convert.
[..]
>> @@ -243,10 +243,10 @@ struct uart_port {
>> unsigned long sysrq; /* sysrq timeout */
>> unsigned int sysrq_ch; /* char for sysrq */
>> unsigned char has_sysrq;
>> + unsigned char sysrq_seq; /* index in sysrq_toggle_seq */
>
> unsigned int?
>
> Or maybe set a maximum length of MAGIC_SYSRQ_SERIAL_SEQUENCE.
I think, 256 chars should be enough to send on serial (c)
I'm not aware of a way to put the max string length in Kconfig, so I did
in the patch:
BUILD_BUG_ON(ARRAY_SIZE(sysrq_toggle_seq) >=
sizeof(port->sysrq_seq)*U8_MAX);
Do you have something more elegant in your mind?
Thanks,
Dmitry
next prev parent reply other threads:[~2020-01-10 22:10 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-09 21:54 [PATCH-next 0/3] serial/sysrq: Add MAGIC_SYSRQ_SERIAL_SEQUENCE Dmitry Safonov
2020-01-09 21:54 ` [PATCH-next 1/3] serial_core: Move sysrq functions from header file Dmitry Safonov
2020-01-10 16:50 ` Greg Kroah-Hartman
2020-01-09 21:54 ` [PATCH-next 2/3] sysctl/sysrq: Remove __sysrq_enabled copy Dmitry Safonov
2020-01-10 3:19 ` Iurii Zaikin
2020-01-10 21:48 ` Dmitry Safonov
2020-01-10 16:40 ` Greg Kroah-Hartman
2020-01-10 21:45 ` Dmitry Safonov
2020-01-10 22:01 ` Greg Kroah-Hartman
2020-01-09 21:54 ` [PATCH-next 3/3] serial/sysrq: Add MAGIC_SYSRQ_SERIAL_SEQUENCE Dmitry Safonov
2020-01-09 23:53 ` Randy Dunlap
2020-01-10 22:02 ` Dmitry Safonov
2020-01-10 16:46 ` Greg Kroah-Hartman
2020-01-10 22:32 ` Dmitry Safonov
2020-01-14 19:10 ` Dmitry Safonov
2020-01-15 12:42 ` Greg Kroah-Hartman
2020-01-10 16:50 ` Joe Perches
2020-01-10 22:10 ` Dmitry Safonov [this message]
2020-01-11 14:08 ` Joe Perches
2020-01-10 19:01 ` kbuild test robot
2020-01-10 19:20 ` kbuild test robot
2020-01-11 10:52 ` kbuild test robot
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