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Subject: Re: [Intel-wired-lan] [PATCH 2/2] igc: wait for the MAC copy when
 enabled MAC passthrough
To:     Aaron Ma <aaron.ma@canonical.com>, jesse.brandeburg@intel.com,
        anthony.l.nguyen@intel.com, davem@davemloft.net, kuba@kernel.org,
        intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        "Edri, Michael" <michael.edri@intel.com>,
        "Ruinskiy, Dima" <dima.ruinskiy@intel.com>,
        "Shalev, Avi" <avi.shalev@intel.com>
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 <ad3d2d01-1d0a-8887-b057-e6a9531a05f4@canonical.com>
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 <96106dfe-9844-1d9d-d865-619d78a0d150@canonical.com>
From:   "Neftin, Sasha" <sasha.neftin@intel.com>
Message-ID: <47117935-10d6-98e0-5894-ba104912ce25@intel.com>
Date:   Thu, 8 Jul 2021 07:24:35 +0300
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On 7/6/2021 09:46, Aaron Ma wrote:
> 
> On 7/5/21 7:54 PM, Neftin, Sasha wrote:
>> Hello Aaron, Thanks to point me on this document. I see... This is 
>> recommendation for Windows driver. Anyway, "delay" approach is 
>> error-prone. We need rather ask for MNG FW confirmation (message) that 
>> MAC address is copied.
>> Can we call (in case we know that MNG FW copied MAC address):
>> igc_rar_set (method from igc_mac.c), update the mac.addr and then 
>> perform": memcpy(netdev->dev_addr, hw->mac.addr, netdev->addr_len);?
> 
> Without delay, after igc_rar_set, the MAC address is all 0.
> The MAC addr is the from dock instead of MAC passthrough with the 
> original driver.
I would to like suggest checking the following direction:
1. principal question: can we update the netdev device address after it 
is already set during probe? I meant perform another:
memcpy(netdev->dev_addr, hw->mac.addr, netdev->addr_len) up to demand
2. We need to work with Intel's firmware engineer/group and define the 
message/event: MAC addressis changed and should be updated.
As I know MNG FW updates shadow registers. Since shadow registers are 
different from RAL/RAH registers - it could be a notification that the 
MAC address changed. Let's check it.
> 
> Thanks,
> Aaron