linux-kernel - Re: [07/18] thunderbolt: Handle rejected Thunderbolt devices

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Message-ID: <20180226194645.GA3774@lahna.fi.intel.com>
Date:   Mon, 26 Feb 2018 21:46:45 +0200
From:   Mika Westerberg <mika.westerberg@...ux.intel.com>
To:     Jeremy McNicoll <jmcnicol@...hat.com>
Cc:     linux-kernel@...r.kernel.org,
        Andreas Noever <andreas.noever@...il.com>,
        Michael Jamet <michael.jamet@...el.com>,
        Yehezkel Bernat <yehezkel.bernat@...el.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Mario.Limonciello@...l.com,
        Radion Mirchevsky <radion.mirchevsky@...el.com>
Subject: Re: [07/18] thunderbolt: Handle rejected Thunderbolt devices

On Mon, Feb 26, 2018 at 11:28:16AM -0800, Jeremy McNicoll wrote:
> On 2018-02-26 5:38 AM, Mika Westerberg wrote:
> > On Mon, Feb 26, 2018 at 12:20:29PM +0200, Mika Westerberg wrote:
> > > On Thu, Feb 22, 2018 at 03:17:38PM -0800, Jeremy McNicoll wrote:
> > > > > +	if (pkg->link_info & ICM_LINK_INFO_REJECTED) {
> > > > > +		tb_info(tb, "switch at %u.%u was rejected by ICM firmware\n",
> > > > > +			link, depth);
> > > > 
> > > > This kind of condition sounds more like an error instead of info.
> > > > Please bump this up to tb_WARN/tb_warn ideally tb_err().
> > > 
> > > No, this is not an error.
> > 
> > To be more clear, it is totally fine to have the firmware to reject some
> > devices. For example in case of the new usbonly security level the
> > firmware rejects other devices but the first.
> > 
> 
> Ok. Is that kind of information available to the kernel?  What security
> mode we are in?
> 
> ie) if (LINK_REJECTED && !USB_SECURITY)
>        print "Error switch %u was rejected since its not usbonly"
>     endif
> 
> I am sure something like that simplified pseudo code above would
> be somewhat useful to users when debugging.

That's why it is on info level so it goes to dmesg but does not scare
the user :-)