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>,
Iurii Zaikin <yzaikin@google.com>, Jiri Slaby <jslaby@suse.com>,
Randy Dunlap <rdunlap@infradead.org>,
Vasiliy Khoruzhick <vasilykh@arista.com>,
linux-serial@vger.kernel.org
Subject: Re: [PATCHv2-next 2/3] serial/sysrq: Add MAGIC_SYSRQ_SERIAL_SEQUENCE
Date: Tue, 14 Jan 2020 17:36:59 +0000 [thread overview]
Message-ID: <a8d1a5df-8c72-049f-3bb4-5fae0166d760@arista.com> (raw)
In-Reply-To: <24455cb643415cf9379bb8343525b844ead4236b.camel@perches.com>
Hi Joe,
On 1/14/20 5:30 PM, Joe Perches wrote:
> On Tue, 2020-01-14 at 17:19 +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.
>
> Hi again Dmitry. trivia:
>
>> diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
> []
>> +/**
>> + * uart_try_toggle_sysrq - Enables SysRq from serial line
>> + * @port: uart_port structure where char(s) after BREAK met
>> + * @ch: new character in the sequence after received BREAK
>> + *
>> + * Enables magic SysRq when the required sequence is met on port
>> + * (see CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE).
>> + *
>> + * Returns 0 if @ch is out of enabling sequence and should be
>> + * handled some other way, 1 if @ch was consumed.
>> + */
>
> Normally bool functions return values are true/false not 1/0.
I agree. Though, somehow it seems to me that `return 1` is a bit closer
to "one character consumed" than "return true".
Again, no hard feelings, just a preference.
I can change those returns to bools if you insist :)
>
>> +static bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch)
>> +{
>> + if (ARRAY_SIZE(sysrq_toggle_seq) <= 1)
>> + return 0;
>
> return false;
>
> etc...
>
>
Thanks,
Dmitry
next prev parent reply other threads:[~2020-01-14 17:37 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-14 17:19 [PATCHv2-next 0/3] serial/sysrq: Add MAGIC_SYSRQ_SERIAL_SEQUENCE Dmitry Safonov
2020-01-14 17:19 ` [PATCHv2-next 1/3] sysctl/sysrq: Remove __sysrq_enabled copy Dmitry Safonov
2020-01-15 12:36 ` Greg Kroah-Hartman
2020-02-23 12:08 ` Dmitry Safonov
2020-02-23 12:10 ` Dmitry Safonov
2020-01-14 17:19 ` [PATCHv2-next 2/3] serial/sysrq: Add MAGIC_SYSRQ_SERIAL_SEQUENCE Dmitry Safonov
2020-01-14 17:30 ` Joe Perches
2020-01-14 17:36 ` Dmitry Safonov [this message]
2020-01-14 17:51 ` Randy Dunlap
2020-01-14 17:19 ` [PATCHv2-next 3/3] serial_core: Remove unused member in uart_port Dmitry Safonov
2020-01-14 17:36 ` Joe Perches
2020-01-14 17:47 ` Dmitry Safonov
2020-01-14 17:56 ` Greg Kroah-Hartman
2020-01-14 18:32 ` Joe Perches
2020-01-14 18:43 ` Dmitry Safonov
2020-01-15 12:40 ` Greg Kroah-Hartman
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