[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Message-ID: <f422b4f7-75ca-8337-e099-fea9cf879b4c@gmail.com>
Date: Mon, 4 Jul 2022 08:35:57 -0700
From: Florian Fainelli <f.fainelli@...il.com>
To: Jiri Slaby <jirislaby@...nel.org>,
Florian Fainelli <f.fainelli@...il.com>,
linux-serial@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, Doug Berger <opendmb@...il.com>,
Al Cooper <alcooperx@...il.com>,
Broadcom internal kernel review list
<bcm-kernel-feedback-list@...adcom.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: Re: [PATCH v2] serial: 8250_bcm7271: Save/restore RTS in
suspend/resume
On 7/3/2022 11:40 PM, Jiri Slaby wrote:
> On 29. 06. 22, 18:02, Florian Fainelli wrote:
>> From: Doug Berger <opendmb@...il.com>
>>
>> Commit 9cabe26e65a8 ("serial: 8250_bcm7271: UART errors after resuming
>> from S2") prevented an early enabling of RTS during resume, but it did
>> not actively restore the RTS state after resume.
>>
>> Fixes: 9cabe26e65a8 ("serial: 8250_bcm7271: UART errors after resuming
>> from S2")
>> Signed-off-by: Doug Berger <opendmb@...il.com>
>> Signed-off-by: Florian Fainelli <f.fainelli@...il.com>
>> ---
>> drivers/tty/serial/8250/8250_bcm7271.c | 24 ++++++++++++++++++------
>> 1 file changed, 18 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/tty/serial/8250/8250_bcm7271.c
>> b/drivers/tty/serial/8250/8250_bcm7271.c
>> index 9b878d023dac..b9cea38c8aff 100644
>> --- a/drivers/tty/serial/8250/8250_bcm7271.c
>> +++ b/drivers/tty/serial/8250/8250_bcm7271.c
> ...
>> @@ -1180,7 +1184,15 @@ static int __maybe_unused
>> brcmuart_resume(struct device *dev)
>> start_rx_dma(serial8250_get_port(priv->line));
>> }
>> serial8250_resume_port(priv->line);
>> - port->mctrl = priv->saved_mctrl;
>> +
>> + if (priv->saved_mctrl & TIOCM_RTS) {
>> + /* Restore RTS */
>> + spin_lock_irqsave(&port->lock, flags);
>> + port->mctrl |= TIOCM_RTS;
>> + spin_unlock_irqrestore(&port->lock, flags);
>> + port->ops->set_mctrl(port, port->mctrl);
>
> Calling ->set_mctrl w/o port->lock doesn't look really safe.
Good point, I will check with Doug whether this was intentional and if
so, why, and if not why should we move it up under the spinlock.
Thanks!
--
Florian
Powered by blists - more mailing lists