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Date:   Mon, 17 Sep 2018 07:03:17 -0700
From:   Jakub Kicinski <jakub.kicinski@netronome.com>
To:     Sasha Levin <Alexander.Levin@microsoft.com>
Cc:     "stable@vger.kernel.org" <stable@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "David S . Miller" <davem@davemloft.net>
Subject: Re: [PATCH AUTOSEL 4.14 52/87] nfp: fail probe if serial or
 interface id is missing
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In-Reply-To: <20180917030220.245686-52-alexander.levin@microsoft.com>
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        <20180917030220.245686-52-alexander.levin@microsoft.com>
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On Mon, 17 Sep 2018 03:02:55 +0000, Sasha Levin wrote:
> From: Jakub Kicinski <jakub.kicinski@netronome.com>
> 
> [ Upstream commit 18aa5b180f00a10c2f63944b4f0ab116bf8ea19b ]
> 
> On some platforms with broken ACPI tables we may not have access
> to the Serial Number PCIe capability.  This capability is crucial
> for us for switchdev operation as we use serial number as switch ID,
> and for communication with management FW where interface ID is used.
> 
> If we can't determine the Serial Number we have to fail device probe.
> 
> Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
> Signed-off-by: David S. Miller <davem@davemloft.net>
> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>

If the problem occurs the driver would usually fail to probe anyway
(e.g. due to missing SR-IOV capability), just without providing any
clear message why.  So the patch is not of huge importance, but I'm 
not opposed to back porting it.

I should've put this info in the commit message, my bad.