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Subject: Re: Thunderbolt DP oddity on v5.2.9 on iMac 12,2
From:   Brad Campbell <lists2009@fnarfbargle.com>
To:     Mika Westerberg <mika.westerberg@linux.intel.com>
Cc:     linux-kernel@vger.kernel.org, michael.jamet@intel.com,
        YehezkelShB@gmail.com
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Message-ID: <2efea088-fb11-0daf-8c39-f7691e2cf075@fnarfbargle.com>
Date:   Wed, 28 Aug 2019 17:34:00 +0800
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On 28/8/19 5:12 pm, Brad Campbell wrote:
> On 28/8/19 3:33 pm, Mika Westerberg wrote:

>> I'm suspecting that the boot firmware does configure second DP path also
>> and we either fail to discover it properly or the boot firmware fails to
>> set it up.
>>
>> Also if you boot with one monitor connected and then connect another
>> (when the system is up) does it work then?
> 
> Umm.. so this is where it gets weird. No it doesn't. Apparently it fails 
> to configure the first monitor it finds. This is the one the Apple 
> bootcamp firmware configures at boot.
> 

Ok just to clarify it appears I've been booting EFI and bypassing the 
Bootcamp BIOS emulation for a few years. So, that made no difference.