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Sender: Larry Finger <larry.finger@gmail.com>
Message-ID: <c06e862c-e5b7-4459-aaed-4f69c3881b84@lwfinger.net>
Date: Fri, 8 Dec 2023 10:17:00 -0600
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Subject: Re: [PATCH] wifi: rtw88: Use random MAC when efuse MAC invalid
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To: Chris Morgan <macroalpha82@gmail.com>, linux-wireless@vger.kernel.org
Cc: kvalo@kernel.org, pkshih@realtek.com,
 Chris Morgan <macromorgan@hotmail.com>
References: <20231208150739.129753-1-macroalpha82@gmail.com>
From: Larry Finger <Larry.Finger@lwfinger.net>
In-Reply-To: <20231208150739.129753-1-macroalpha82@gmail.com>
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On 12/8/23 09:07, Chris Morgan wrote:
> From: Chris Morgan <macromorgan@hotmail.com>
> 
> When the MAC address read from the efuse data is invalid, warn the
> user and use a random MAC address instead.
> 
> On a device I am currently using (Anbernic RG-ARC) with a rtw8821cs
> the efuse appears to be incompletely/improperly programmed. The MAC
> address reads as ff:ff:ff:ff:ff:ff. When networkmanager attempts to
> initiate a connection (and I haven't hard-coded a MAC address or
> set it to random) it fails to establish a connection.
> 
> Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
> ---
>   drivers/net/wireless/realtek/rtw88/main.c | 5 +++++
>   1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/net/wireless/realtek/rtw88/main.c b/drivers/net/wireless/realtek/rtw88/main.c
> index 4a33d2e47f33..6d22628129d0 100644
> --- a/drivers/net/wireless/realtek/rtw88/main.c
> +++ b/drivers/net/wireless/realtek/rtw88/main.c
> @@ -2008,6 +2008,11 @@ static int rtw_chip_efuse_info_setup(struct rtw_dev *rtwdev)
>   	efuse->ext_pa_5g = efuse->pa_type_5g & BIT(0) ? 1 : 0;
>   	efuse->ext_lna_2g = efuse->lna_type_5g & BIT(3) ? 1 : 0;
>   
> +	if (!is_valid_ether_addr(efuse->addr)) {
> +		eth_random_addr(efuse->addr);
> +		dev_warn(rtwdev->dev, "efuse MAC invalid, using random\n");
> +	}
> +
>   out_disable:
>   	rtw_chip_efuse_disable(rtwdev);
>   

Reviewed by Larry Finger <Larry.Finger@lwfinger.net>

Thanks for this patch.

There are a number of SDIO devices known to me with improperly coded EFUSE 
values. It seems that RTW8723DS chips perform poorly even when given a valid MAC 
address. Is this also true for RTW8821CS chips?

Larry