From: Peter Zijlstra <peterz@infradead.org>
To: Ingo Molnar <mingo@kernel.org>
Cc: Lu Baolu <baolu.lu@linux.intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Mathias Nyman <mathias.nyman@linux.intel.com>,
Ingo Molnar <mingo@redhat.com>,
tglx@linutronix.de, linux-usb@vger.kernel.org, x86@kernel.org,
linux-kernel@vger.kernel.org, Jiri Slaby <jslaby@suse.cz>
Subject: Re: [PATCH v5 1/4] usb: dbc: early driver for xhci debug capability
Date: Thu, 26 Jan 2017 11:28:48 +0100 [thread overview]
Message-ID: <20170126102848.GZ6515@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20170126071937.GA3399@gmail.com>
On Thu, Jan 26, 2017 at 08:19:37AM +0100, Ingo Molnar wrote:
>
> * Lu Baolu <baolu.lu@linux.intel.com> wrote:
>
> > Fair enough.
> >
> > USB connection is stable enough, unless the user unplugs the
> > USB cable during debugging.
>
> What does the hardware do in this case? The XHCI registers are in the host
> hardware, so they won't disappear, right? Is there some cable connection status
> bit we can extract without interrupts?
>
> I.e. if there's any polling component then it would be reasonable to add an error
> component: poll the status and if it goes 'disconnected' then disable early-printk
> altogether in this case and trigger an emergency printk() so that there's chance
> that the user notices [if the system does not misbehave otherwise].
That'll be fun when printk() == early_printk() :-)
I myself wouldn't mind the system getting stuck until the link is
re-established. My own damn fault for taking that cable out etc.
next prev parent reply other threads:[~2017-01-26 10:29 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-15 6:02 [PATCH v5 0/4] usb: early: add support for early printk through USB3 debug port Lu Baolu
2016-11-15 6:02 ` [PATCH v5 1/4] usb: dbc: early driver for xhci debug capability Lu Baolu
2017-01-19 9:37 ` Ingo Molnar
2017-01-20 2:47 ` Lu Baolu
2017-01-22 9:04 ` Ingo Molnar
2017-01-24 4:44 ` Lu Baolu
2017-01-24 8:20 ` Ingo Molnar
2017-01-25 5:28 ` Lu Baolu
2017-01-25 9:23 ` Ingo Molnar
2017-01-25 9:57 ` Peter Zijlstra
2017-01-25 12:27 ` Lu Baolu
2017-01-25 14:38 ` Peter Zijlstra
2017-01-25 15:51 ` Lu Baolu
2017-01-25 16:16 ` Peter Zijlstra
2017-01-26 3:37 ` Lu Baolu
2017-01-26 7:19 ` Ingo Molnar
2017-01-26 7:49 ` Lu Baolu
2017-01-26 8:17 ` Ingo Molnar
2017-01-26 10:28 ` Peter Zijlstra [this message]
2017-01-26 16:01 ` Ingo Molnar
2017-01-26 17:39 ` Peter Zijlstra
2017-01-27 6:51 ` Ingo Molnar
2017-02-09 5:59 ` Lu Baolu
2017-01-26 7:22 ` Ingo Molnar
2017-02-09 7:37 ` Lu Baolu
2017-01-25 12:17 ` Lu Baolu
2017-01-26 3:26 ` Lu Baolu
2016-11-15 6:02 ` [PATCH v5 2/4] x86: add support for earlyprintk via USB3 debug port Lu Baolu
2017-01-19 9:38 ` Ingo Molnar
2017-01-20 2:48 ` Lu Baolu
2016-11-15 6:02 ` [PATCH v5 3/4] usb: serial: usb_debug: add support for dbc debug device Lu Baolu
2017-01-19 9:39 ` Ingo Molnar
2017-01-20 2:50 ` Lu Baolu
2016-11-15 6:02 ` [PATCH v5 4/4] usb: doc: add document for USB3 debug port usage Lu Baolu
2017-01-19 9:41 ` Ingo Molnar
2017-01-20 2:53 ` Lu Baolu
2017-01-18 6:20 ` [PATCH v5 0/4] usb: early: add support for early printk through USB3 debug port Lu Baolu
2017-01-19 9:06 ` Greg Kroah-Hartman
2017-01-19 9:09 ` Ingo Molnar
2017-01-19 11:24 ` Mathias Nyman
2017-01-19 9:12 ` Ingo Molnar
2017-01-20 2:56 ` Lu Baolu
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