linux-kernel - Re: [PATCH] serial_core: Change UART PM state to OFF on failure

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Date:	Fri, 10 Jun 2016 11:24:44 +0530
From:	Pramod Gurav <pramod.gurav@...aro.org>
To:	Peter Hurley <peter@...leysoftware.com>
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>, jslaby@...e.com,
	linux-serial@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] serial_core: Change UART PM state to OFF on failure

Hi Peter,

On 8 June 2016 at 22:17, Peter Hurley <peter@...leysoftware.com> wrote:
> Hi Pramod,
>
> On 05/06/2016 02:46 AM, Pramod Gurav wrote:
>> uart_change_pm is used to turn on the UART controller resources and
>> change UART's PM status. On failure to allocate pages the controller
>> be left in ON state. This will change the state to OFF on failure.
>>
>> Signed-off-by: Pramod Gurav <pramod.gurav@...aro.org>
>> ---
>>  drivers/tty/serial/serial_core.c | 5 +++--
>>  1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
>> index 62fe368..58af2e9 100644
>> --- a/drivers/tty/serial/serial_core.c
>> +++ b/drivers/tty/serial/serial_core.c
>> @@ -156,9 +156,10 @@ static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
>>       if (!state->xmit.buf) {
>>               /* This is protected by the per port mutex */
>>               page = get_zeroed_page(GFP_KERNEL);
>> -             if (!page)
>> +             if (!page) {
>
>         if (!uart_console(uport))
>
> Otherwise, you'll be powering off the console.
>

Agree. Should take care console is not disabled.
> Just out of curiosity, did you actually hit this error?
No, I did not. I thought we should not be leaving port power enabled
in error case.

Thanks for review and comments.

Regards,
Pramod