Subject: Re: [PATCH v2] console: use first console if stdout-path device
 doesn't appear
To: Paul Burton <paul.burton@imgtec.com>,
        Michael Ellerman <mpe@ellerman.id.au>
References: <87zill13z8.fsf@concordia.ellerman.id.au>
 <20161031121455.23280-1-paul.burton@imgtec.com>
 <1593250.MZpe3pfUW6@np-p-burton>
Cc: Andreas Schwab <schwab@linux-m68k.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Borislav Petkov <bp@suse.de>, Petr Mladek <pmladek@suse.com>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Tejun Heo <tj@kernel.org>, linux-kernel@vger.kernel.org,
        linuxppc-dev@lists.ozlabs.org
From: Larry Finger <Larry.Finger@lwfinger.net>
Message-ID: <8c0538ec-6922-3c43-d944-8ac9cd57a708@lwfinger.net>
Date: Mon, 31 Oct 2016 14:21:30 -0500
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On 10/31/2016 10:50 AM, Paul Burton wrote:
> On Monday, 31 October 2016 12:14:55 GMT Paul Burton wrote:
>> If a device tree specified a preferred device for kernel console output
>> via the stdout-path or linux,stdout-path chosen node properties there's
>> no guarantee that it will have specified a device for which we have a
>> driver. It may also be the case that we do have a driver but it doesn't
>> call of_console_check() to register as a preferred console (eg. offb
>> driver as used on powermac systems). In these cases try to ensure that
>> we provide some console output by enabling the first usable registered
>> console, which we keep track of with the of_fallback_console variable.
>>
>> Tested in QEMU with a PowerPC pseries_defconfig kernel.
>
> Actually whilst this fixes the output in QEMU it has other problems. I'm still
> digging...

As expected, it does n ot work with 4.9-rc3 on the real PowerPC.

Larry