Re: [PATCH] serial: 8250: Default SERIAL_OF_PLATFORM to SERIAL_8250

From: Florian Fainelli <f.fainelli@gmail.com>
To: Guenter Roeck <linux@roeck-us.net>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
	linux-kernel@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>
Subject: Re: [PATCH] serial: 8250: Default SERIAL_OF_PLATFORM to SERIAL_8250
Date: Thu, 20 Dec 2018 20:28:39 -0800	[thread overview]
Message-ID: <634702e3-41db-3761-b562-5afdc928b3d3@gmail.com> (raw)
In-Reply-To: <20181220173844.GA5838@roeck-us.net>

Le 12/20/18 à 9:38 AM, Guenter Roeck a écrit :
> On Thu, Dec 20, 2018 at 04:21:11PM +0100, Greg Kroah-Hartman wrote:
>> On Wed, Nov 14, 2018 at 05:11:25PM -0800, Guenter Roeck wrote:
>>> On Thu, Nov 01, 2018 at 11:26:06AM -0700, Florian Fainelli wrote:
>>>> It is way too easy to miss enabling SERIAL_OF_PLATFORM which would
>>>> result in the inability for the kernel to have a valid console device,
>>>> which can be seen with:
>>>>
>>>> Warning: unable to open an initial console.
>>>>
>>>> and then:
>>>>
>>>> Run /init as init process
>>>> Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000100
>>>>
>>>> Since SERIAL_OF_PLATFORM already depends on SERIAL_8250 && OF there
>>>> really is no drawback to defaulting this config to the value of
>>>> SERIAL_8250.
>>>>
>>>> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
>>>> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>>>
>>> This patch results in situations where CONFIG_SERIAL_OF_PLATFORM is now
>>> defined where it was not previously. Example mpc85xx_defconfig. This in
>>> turn results in boot failures for those configurations, with an error
>>> message of
>>>
>>> of_serial: probe of e0004500.serial failed with error -22
>>>
>>> which wasn't seen before.
>>>
>>> Not sure if replacing a potential problem with a real one is really an
>>> improvement.`
>>
>> What ever was the result of this long thread?  Should I revert
>> something?  Or was a patch proposed?
>>
> The problem still exists in next-20181220.

I submitted a tentative patch to fix the problem, discussed it with
Michael and he had an alternative patch to 8250_core.c that should work
equally well though I was worried more breakage could be created that
way. Since clearly we have not been able to make much progress, maybe a
reversion of the original patch is appropriate, yes it's now sent a as a
reply to this mail!	

> 
> Unfortunately this is now just one failure of many in -next. I see more
> than 90 boot failures (out of ~330) there, not counting the build failures.
> And that is on a good day.
> 
> Guenter
> 

-- 
Florian