linux-kernel - Re: [PATCH] serial/core: Initialize the console pm state

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Date:	Mon, 6 Oct 2014 14:57:37 +0530
From:	Sudhir Sreedharan <ssreedharan@...sta.com>
To:	Kevin Hilman <khilman@...nel.org>
Cc:	linux-serial@...r.kernel.org, gregkh@...uxfoundation.org,
	jslaby@...e.cz, lkml <linux-kernel@...r.kernel.org>,
	olof@...om.net,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH] serial/core: Initialize the console pm state

Hi Kevin,

On Wed, Oct 1, 2014 at 10:57 PM, Kevin Hilman <khilman@...nel.org> wrote:
> On Sun, Sep 21, 2014 at 11:30 PM, Sudhir Sreedharan
> <ssreedharan@...sta.com> wrote:
>> For console devices having UART_CAP_SLEEP capability, the uart_pm_state has
>> to be initialized to UART_PM_STATE_ON. Otherwise the LCR regiser values
>> are reinitialized when uart_change_pm is called from uart_configure_port.
>>
>> Signed-off-by: Sudhir Sreedharan <ssreedharan@...sta.com>
>
> Multiple boot failures on ARM[1] were bisected down to this patch.
>
> How was this patch tested, and on which platforms?



This patch was tested on x86-64(haswell) board, which uses ST16650V2
uart(which has UART_CAP_SLEEP).
While serial driver gets initialized, console port LCR register is
getting reinitalized to 0.
Then boot logs will be seen as garbage characters.

I will re-check why this failed on the boards/archs you mentioned.

Thanks,
Sudhir
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