Thread (10 messages) flat view 10 messages, 4 authors, 2021-08-26

Re: [PATCH net-next 1/2] net: pcs: xpcs: enable skip xPCS soft reset

From: Wong Vee Khee <hidden>
Date: 2021-08-10 23:55:42
Also in: lkml, netdev

Hi Andrew,
On Mon, Aug 09, 2021 at 03:35:09PM +0200, Andrew Lunn wrote:
On Mon, Aug 09, 2021 at 06:22:28PM +0800, Wong Vee Khee wrote:
quoted
From: Michael Sit Wei Hong <redacted>

Unlike any other platforms, Intel AlderLake-S uses Synopsys SerDes where
all the SerDes PLL configurations are controlled by the xPCS at the BIOS
level. If the driver perform a xPCS soft reset on initialization, these
settings will be switched back to the power on reset values.

This changes the xpcs_create function to take in an additional argument
to check if the platform request to skip xPCS soft reset during device
initialization.
Why not just call into the BIOS and ask it to configure the SERDES?
Isn't that what ACPI is all about, hiding the details from the OS? Or
did the BIOS writers not add a control method to do this?

    Andrew
BIOS does configured the SerDes. The problem here is that all the
configurations done by BIOS are being reset at xpcs_create().

We would want user of the pcs-xpcs module (stmmac, sja1105) to have
control whether or not we need to perform to the soft reset in the
xpcs_create() call.

Hope that explained.

Regards,
 VK

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