Re: [PATCH] usbnet: Set duplex status to unknown in the absence of MII
From: Andrew Lunn <andrew@lunn.ch>
Date: 2025-07-21 13:51:16
Also in:
linux-usb
On Mon, Jul 21, 2025 at 03:10:22PM +0800, yicongsrfy@163.com wrote:
From: Yi Cong <redacted> CDC device don't use mdio to get link status, duplex is set half as default. Now cdc_ncm can't get duplex, set it UNKNOWN instead of half which might actually be in an error state.
It appears that CDC has a transfer to report the link status: usbnet_cdc_status(). There is a u32 which contains the link speed. Is the duplex also included in this transfer? What does the standard say about duplex? Are 1/2 duplex modes are supported? Is it clear stated they are not supported? 1G/half not be supported depending on the MAC/PHY pair? Andrew