From: Oliver Neukum <oliver@neukum•org>
To: Ming Lei <tom.leiming@gmail•com>
Cc: Dan Williams <dcbw@redhat•com>,
Elina Pasheva <epasheva@sierrawireless•com>,
Network Development <netdev@vger•kernel.org>,
linux-usb <linux-usb@vger•kernel.org>,
Rory Filer <rfiler@sierrawireless•com>, Phil Sutter <phil@nwl•cc>,
Alan Stern <stern@rowland•harvard.edu>
Subject: Re: [PATCH 1/2 v5] usbnet: allow status interrupt URB to always be active
Date: Fri, 19 Apr 2013 10:25:04 +0200 [thread overview]
Message-ID: <1436202.ggQbKKzqIM@linux-5eaq.site> (raw)
In-Reply-To: <CACVXFVP=DrbPinLt_rxYETmRYONt-MOsmhAv_O8EcrnpbVohMA@mail.gmail.com>
On Thursday 18 April 2013 11:51:25 Ming Lei wrote:
> On Wed, Apr 17, 2013 at 2:55 PM, Oliver Neukum <oliver@neukum•org> wrote:
>
> > If we have a function for starting a status URB we want to use it whenever
> > it applies, that is also when we need to poll status for internal reason while
> > an interface is up.
>
> For other non-sierra usbnet devices, when an interface is up, the status URB
> is scheduled in open() and needn't the API.
But that is the very point. This API is used from _within_ open.
We cannot make every open() use GFP_NOIO
> > You don't need to understand it any more than you need to understand
> > the rule for usb_submit_urb(). The rules are the very same. There is no
> > special effort here.
>
> No, there isn't one rule for the corner case here, and the corner case should
> have existed in probe() or cancel queue with reset of all USB drivers, instead
> of usbnet only.
The same rule applies to usb_submit_urb(), too.
> Also the rule 3 is a bit obscure, maybe not correct, at least there are much
> GFP_KERNEL usages in kthread of usbnet. I am wondering if there are
> other usbnet specific memflags rules except for 1 & 6.
>
> Strictly speaking, the rule 5 isn't correct, since it might trigger the corner
> case you mentioned, right?
>
> I think we need to review the memflags part of usb_submit_urb() doc now.
Yes.
> +int usbnet_status_start(struct usbnet *dev, gfp_t mem_flags)
> +{
> + int ret = 0;
> +
> + WARN_ON_ONCE(dev->interrupt == NULL);
> + if (dev->interrupt) {
> + mutex_lock(&dev->interrupt_mutex);
>
> ....
>
> +}
>
> Obviously, the API can't be called in atomic context, and putting runtime PM
> inside is reasonable and correct.
Yes, but how is it relevant. What allows us to conclude that a driver does not want
runtime PM while a status URB is running?
> > I meant block suspend in the sense of disallowing it. Which is very problematic.
> > The CDC protocols generally support remote wakeup for status information,
> > so we need to be able to sleep while status is running to accomodate devices
> > which are intended to be always online.
>
> At least now, for non-sierra drivers, it needn't the API to schedule status URB
> which will be started in normal open() path, so won't power on device runtime
> unnecessarily. That is what I say the API shouldn't be for a general usage, :-)
But many drivers, e.g. cdc-ether, cdc-ncm and cdc-mbim want to be able
to runtime suspend while the device is open.
Regards
Oliver
next prev parent reply other threads:[~2013-04-19 8:24 UTC|newest]
Thread overview: 89+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-27 14:12 strange behaviour of MC7700 with sierra_net Phil Sutter
[not found] ` <20110727141246.GC29616-2COwY06ShZsYt6otZODPyA@public.gmane.org>
2011-07-27 19:40 ` Dan Williams
[not found] ` <1311795643.17655.13.camel-wKZy7rqYPVb5EHUCmHmTqw@public.gmane.org>
2011-07-28 16:32 ` Phil Sutter
[not found] ` <8F90F944E50427428C60E12A34A309D23424BB0F25@carmd-exchmb01.sierrawireless.local>
[not found] ` <8F90F944E50427428C60E12A34A309D23424BB0F25-3qf8vkpM5jTbmvMHnzRVpW3Pdy6AhKVLXbPIYa3/oNjDOqzlkpFKJg@public.gmane.org>
2011-08-04 16:38 ` Phil Sutter
2013-01-04 16:48 ` [PATCH 1/2] usbnet: allow status interrupt URB to always be active Dan Williams
2013-01-04 16:51 ` [PATCH 2/2] sierra_net: keep status interrupt URB active over netdev open/close Dan Williams
[not found] ` <1357318289.5370.19.camel-wKZy7rqYPVb5EHUCmHmTqw@public.gmane.org>
2013-02-06 18:42 ` [PATCH 2/2 v2] sierra_net: fix issues with SYNC/RESTART messages and interrupt pipe setup Dan Williams
[not found] ` <1360176176.11742.16.camel-wKZy7rqYPVb5EHUCmHmTqw@public.gmane.org>
2013-02-06 20:17 ` Oliver Neukum
2013-02-07 21:09 ` Dan Williams
2013-02-06 21:11 ` Bjørn Mork
2013-02-07 17:06 ` Dan Williams
2013-02-13 11:44 ` Bjørn Mork
2013-02-13 16:34 ` Dan Williams
2013-01-04 22:16 ` [PATCH 1/2] usbnet: allow status interrupt URB to always be active Oliver Neukum
2013-01-05 1:26 ` Dan Williams
[not found] ` <1357349193.19684.3.camel-wKZy7rqYPVb5EHUCmHmTqw@public.gmane.org>
2013-01-05 10:59 ` Bjørn Mork
[not found] ` <87y5g7nbej.fsf-lbf33ChDnrE/G1V5fR+Y7Q@public.gmane.org>
2013-01-07 7:40 ` Oliver Neukum
2013-01-07 15:21 ` Dan Williams
2013-01-11 3:06 ` Ming Lei
2013-01-14 17:23 ` Dan Williams
2013-01-15 1:13 ` Ming Lei
2013-01-05 11:01 ` Oliver Neukum
2013-01-05 11:44 ` Bjørn Mork
2013-01-07 15:25 ` Dan Williams
2013-01-14 17:52 ` Dan Williams
2013-02-06 18:36 ` [PATCH 1/2 v2] " Dan Williams
2013-02-06 20:19 ` Oliver Neukum
2013-03-28 16:30 ` [PATCH 1/2 v3] " Dan Williams
[not found] ` <1364488207.1877.20.camel-wKZy7rqYPVb5EHUCmHmTqw@public.gmane.org>
2013-03-28 16:32 ` [PATCH 2/2 v3] sierra_net: keep status interrupt URB active Dan Williams
[not found] ` <1364488327.1877.22.camel-wKZy7rqYPVb5EHUCmHmTqw@public.gmane.org>
2013-03-29 19:21 ` David Miller
2013-03-29 19:20 ` [PATCH 1/2 v3] usbnet: allow status interrupt URB to always be active David Miller
[not found] ` <CACVXFVMBAzTYZKiE_uSTqr_yB4f7c5_PSnK=LBP6=oWdWwYHfg@mail.gmail.com>
[not found] ` <CACVXFVMBAzTYZKiE_uSTqr_yB4f7c5_PSnK=LBP6=oWdWwYHfg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-04-01 16:04 ` Dan Williams
2013-04-09 23:02 ` [PATCH 1/2 v4] " Dan Williams
2013-04-09 23:05 ` [PATCH 2/2 v4] sierra_net: keep status interrupt URB active Dan Williams
2013-04-10 7:15 ` Oliver Neukum
2013-04-10 14:57 ` Dan Williams
2013-04-10 15:01 ` Oliver Neukum
2013-04-10 7:23 ` [PATCH 1/2 v4] usbnet: allow status interrupt URB to always be active Oliver Neukum
[not found] ` <2328167.HJRXSHNhKT-7ztolUikljGernLeA6q8OA@public.gmane.org>
2013-04-10 12:49 ` Dan Williams
2013-04-10 13:06 ` Oliver Neukum
2013-04-10 13:18 ` Dan Williams
2013-04-10 13:29 ` Oliver Neukum
[not found] ` <1542762.9EJvNHlBNo-7ztolUikljGernLeA6q8OA@public.gmane.org>
2013-04-10 13:54 ` Dan Williams
[not found] ` <1365602083.28888.40.camel-wKZy7rqYPVb5EHUCmHmTqw@public.gmane.org>
2013-04-10 13:58 ` Oliver Neukum
2013-04-10 15:01 ` Dan Williams
2013-04-10 18:10 ` Oliver Neukum
2013-04-10 20:30 ` [PATCH 1/2 v5] " Dan Williams
2013-04-10 21:35 ` Oliver Neukum
[not found] ` <1365625850.22411.1.camel-wKZy7rqYPVb5EHUCmHmTqw@public.gmane.org>
2013-04-10 20:33 ` [PATCH 2/2 v5] sierra_net: keep status interrupt URB active Dan Williams
2013-04-11 2:31 ` [PATCH 1/2 v5] usbnet: allow status interrupt URB to always be active Ming Lei
2013-04-11 6:50 ` Oliver Neukum
2013-04-11 8:06 ` Bjørn Mork
2013-04-11 8:37 ` Ming Lei
2013-04-11 9:59 ` Oliver Neukum
2013-04-11 10:04 ` Bjørn Mork
2013-04-11 10:09 ` Ming Lei
2013-04-11 10:19 ` Ming Lei
[not found] ` <CACVXFVNn9MQr6JLdin=u642Jb-2ZPfVk8YaBmNdhU0_2e7WJqQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-04-11 10:26 ` Bjørn Mork
2013-04-11 10:30 ` Ming Lei
2013-04-11 11:08 ` Bjørn Mork
[not found] ` <87d2u1wci6.fsf-lbf33ChDnrE/G1V5fR+Y7Q@public.gmane.org>
2013-04-11 11:42 ` Ming Lei
[not found] ` <CACVXFVO13tG606nDHth5rEA9jexj1iFHnry5ktrMpm_aGGTSvw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-04-11 11:54 ` Oliver Neukum
2013-04-11 12:16 ` Ming Lei
2013-04-11 8:09 ` Ming Lei
2013-04-11 9:53 ` Oliver Neukum
2013-04-11 10:03 ` Ming Lei
2013-04-11 11:14 ` Oliver Neukum
2013-04-11 12:11 ` Ming Lei
2013-04-11 12:28 ` Oliver Neukum
2013-04-11 12:59 ` Ming Lei
[not found] ` <CACVXFVPPzva+EwjNdxWsg4FufCc0zzzzvhGH_nLv479vT8VcxQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-04-12 6:37 ` Oliver Neukum
2013-04-12 9:42 ` Ming Lei
2013-04-12 10:02 ` Oliver Neukum
2013-04-12 10:08 ` Ming Lei
2013-04-12 10:13 ` Bjørn Mork
2013-04-11 15:28 ` Dan Williams
2013-04-12 7:28 ` Oliver Neukum
2013-04-15 15:59 ` Dan Williams
2013-04-16 1:15 ` Ming Lei
2013-04-16 7:57 ` Oliver Neukum
[not found] ` <1637650.tuYfvStuVJ-7ztolUikljGernLeA6q8OA@public.gmane.org>
2013-04-17 1:56 ` Ming Lei
2013-04-17 6:55 ` Oliver Neukum
[not found] ` <5581442.KzM2iaDSQ0-7ztolUikljGernLeA6q8OA@public.gmane.org>
2013-04-18 3:51 ` Ming Lei
2013-04-19 8:25 ` Oliver Neukum [this message]
2013-04-24 12:31 ` Dan Williams
2013-04-25 13:00 ` Oliver Neukum
[not found] ` <1365548547.23372.2.camel-wKZy7rqYPVb5EHUCmHmTqw@public.gmane.org>
2013-04-10 13:25 ` [PATCH 1/2 v4] " Bjørn Mork
2013-04-10 13:31 ` Oliver Neukum
[not found] ` <1365604263.28888.56.camel@dcbw.foobar.com>
2013-04-10 15:21 ` Bjørn Mork
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1436202.ggQbKKzqIM@linux-5eaq.site \
--to=oliver@neukum$(echo .)org \
--cc=dcbw@redhat$(echo .)com \
--cc=epasheva@sierrawireless$(echo .)com \
--cc=linux-usb@vger$(echo .)kernel.org \
--cc=netdev@vger$(echo .)kernel.org \
--cc=phil@nwl$(echo .)cc \
--cc=rfiler@sierrawireless$(echo .)com \
--cc=stern@rowland$(echo .)harvard.edu \
--cc=tom.leiming@gmail$(echo .)com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox