linux-kernel - Re: [PATCH] usb: xhci: xhci_setup_port_arrays: early -ENODEV if maxports is 0.

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Message-ID: <20241004125716.75c857ae@foxbook>
Date: Fri, 4 Oct 2024 12:57:16 +0200
From: Michał Pecio <michal.pecio@...il.com>
To: olivierdautricourt@...il.com
Cc: gregkh@...uxfoundation.org, linux-kernel@...r.kernel.org,
 linux-usb@...r.kernel.org, mathias.nyman@...el.com
Subject: Re: [PATCH] usb: xhci: xhci_setup_port_arrays: early -ENODEV if
 maxports is 0.

Hi,

> If the controller reports HCSPARAMS1.maxports==0 then we can skip the
> whole function: it would fail later after doing a bunch of unnecessary
> stuff. It can occur on a buggy hardware (the value is driven by external
> signals).

This function runs once during HC initialization, so what's the benefit
of bypassing it? Does it take unusually long time? Does it panic?

It seems to alreday be written to handle such abnormal cases gracefully.

Regards,
Michal