linux-kernel - Re: [PATCH v2] xhci: reduce xhci_handshake timeout in xhci

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Message-ID: <YgpLGGYI0W9mL2gg@kroah.com>
Date:   Mon, 14 Feb 2022 13:29:12 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     Pavankumar Kondeti <quic_pkondeti@...cinc.com>
Cc:     Mathias Nyman <mathias.nyman@...el.com>, linux-usb@...r.kernel.org,
        linux-kernel@...r.kernel.org, quic_ugoswami@...cinc.com,
        Jung Daehwan <dh10.jung@...sung.com>
Subject: Re: [PATCH v2] xhci: reduce xhci_handshake timeout in xhci_reset

On Mon, Feb 14, 2022 at 05:50:16PM +0530, Pavankumar Kondeti wrote:
> From: Daehwan Jung <dh10.jung@...sung.com>
> 
> xhci_reset() is called with interrupts disabled. Waiting 10 seconds for
> controller reset and controller ready operations can be fatal to the
> system when controller is timed out. Reduce the timeout to 1 second
> and print a error message when the time out happens.
> 
> Fixes: 22ceac191211 ("xhci: Increase reset timeout for Renesas 720201 host.")
> Signed-off-by: Daehwan Jung <dh10.jung@...sung.com>
> Signed-off-by: Pavankumar Kondeti <quic_pkondeti@...cinc.com>
> ---
> 
> v2:
> - Add error print statements in the code that change log refers to
> 
>  drivers/usb/host/xhci.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
> index dc357ca..bb9ea3f 100644
> --- a/drivers/usb/host/xhci.c
> +++ b/drivers/usb/host/xhci.c
> @@ -196,9 +196,11 @@ int xhci_reset(struct xhci_hcd *xhci)
>  		udelay(1000);
>  
>  	ret = xhci_handshake(&xhci->op_regs->command,
> -			CMD_RESET, 0, 10 * 1000 * 1000);
> -	if (ret)
> +			CMD_RESET, 0, 1 * 1000 * 1000);
> +	if (ret) {
> +		xhci_err(xhci, "Host controller reset timed out\n");

A timeout is not the only error that could have happened here.  So why
claim that all errors are timeout errors?

How did you test this?

thanks,

greg k-h