From: "Bjørn Mork" <bjorn@mork•no>
To: Ming Lei <ming.lei@canonical•com>
Cc: "David S. Miller" <davem@davemloft•net>,
Greg Kroah-Hartman <gregkh@linuxfoundation•org>,
Jiri Kosina <jkosina@suse•cz>,
Alan Stern <stern@rowland•harvard.edu>,
Oliver Neukum <oneukum@suse•de>,
netdev@vger•kernel.org, linux-usb@vger•kernel.org,
linux-input@vger•kernel.org
Subject: Re: [PATCH 4/7] usbnet: cdc_mbim: don't recover device if suspend fails in system sleep
Date: Tue, 05 Mar 2013 17:08:07 +0100 [thread overview]
Message-ID: <87wqtlommw.fsf@nemi.mork.no> (raw)
In-Reply-To: <CACVXFVMDNtJOp+8jMOuhCBjrqq-L=jicEJBr_=ErG19Vr+7OGw@mail.gmail.com> (Ming Lei's message of "Tue, 5 Mar 2013 23:29:15 +0800")
Ming Lei <ming.lei@canonical•com> writes:
> Yes, USB core will flush any outstanding URBs, but the driver still need
> to deal with suspend failure carefully, for example, suppose usb_resume()
> is called in suspend failure path, and the submitted URBs are killed
> by USB core later. But after the device is wakeup, and the resume() will
> do nothing since the suspend count is leaked. So it is what the patches
> are fixing, and it is better to not depend on the default flushing URBs of
> USB core.
I am starting to wonder why the USB core has combined system suspend and
runtime suspend if we are going to end up with every driver testing
PMSG_IS_AUTO(message) and selecting a completely different code path.
You are right that we will end up with problems if usbnet_resume is
called for a device usbnet hasn't suspended. But I'd still claim that
is a bug in the USB core, which is the one that decided to ignore the
suspend error and still call resume.
I guess proper error handling here require the USB core to see the
interface driver as dead if it fails to suspend on system suspend, and
do forced rebinding on resume.
I am not going to fight this any longer. The per-driver
PMSG_IS_AUTO(message) testing is an ugly workround for a core problem,
but they are already all over the place... Still, please make sure the
drivers all return 0 if they are pretending to suspend. No error code
return if the driver ignores the error.
Bjørn
next prev parent reply other threads:[~2013-03-05 16:09 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-05 4:01 [PATCH 0/7] USB: don't recover device if suspend fails in system sleep Ming Lei
2013-03-05 4:01 ` [PATCH 1/7] USB: adds comment on suspend callback Ming Lei
2013-03-05 13:16 ` Ming Lei
[not found] ` <1362456103-24956-1-git-send-email-ming.lei-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>
2013-03-05 4:01 ` [PATCH 2/7] USB: serial: handle suspend failure path correctly Ming Lei
2013-03-05 4:01 ` [PATCH 3/7] USBHID: don't recover device if suspend fails in system sleep Ming Lei
2013-03-05 4:01 ` [PATCH 4/7] usbnet: cdc_mbim: " Ming Lei
[not found] ` <1362456103-24956-5-git-send-email-ming.lei-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>
2013-03-05 7:09 ` Bjørn Mork
2013-03-05 11:07 ` Ming Lei
2013-03-05 13:46 ` Bjørn Mork
2013-03-05 14:50 ` Ming Lei
2013-03-05 15:03 ` Bjørn Mork
2013-03-05 15:29 ` Ming Lei
2013-03-05 16:08 ` Bjørn Mork [this message]
[not found] ` <87wqtlommw.fsf-lbf33ChDnrE/G1V5fR+Y7Q@public.gmane.org>
2013-03-05 16:54 ` Alan Stern
2013-03-05 17:35 ` Bjørn Mork
2013-03-06 2:51 ` Ming Lei
2013-03-06 3:03 ` Ming Lei
[not found] ` <CACVXFVN=i10cVS3RQ7jGrJAfsC+r2t61z7XOVKWMAMqKKELZCg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-03-06 7:06 ` Bjørn Mork
2013-03-06 7:50 ` Ming Lei
2013-03-06 8:32 ` Bjørn Mork
2013-03-05 4:01 ` [PATCH 5/7] usbnet: smsc95xx: " Ming Lei
2013-03-05 4:01 ` [PATCH 6/7] usbnet: smsc75xx: " Ming Lei
2013-03-05 4:01 ` [PATCH 7/7] usbnet: qmi_wwan: " Ming Lei
[not found] ` <1362456103-24956-8-git-send-email-ming.lei-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>
2013-03-05 7:09 ` Bjørn Mork
2013-03-05 12:27 ` Ming Lei
2013-03-05 5:14 ` [PATCH 0/7] USB: " Ming Lei
2013-03-05 7:03 ` Bjørn Mork
2013-03-05 10:55 ` Ming Lei
2013-03-05 12:50 ` Oliver Neukum
[not found] ` <3703451.5FViJ58GpZ-7ztolUikljGernLeA6q8OA@public.gmane.org>
2013-03-05 13:08 ` Ming Lei
2013-03-05 13:28 ` Oliver Neukum
2013-03-05 14:03 ` Ming Lei
2013-03-05 13:18 ` Bjørn Mork
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