From: Daniel Thompson <daniel.thompson@linaro.org>
To: Sumit Garg <sumit.garg@linaro.org>
Cc: Doug Anderson <dianders@chromium.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-serial@vger.kernel.org,
kgdb-bugreport@lists.sourceforge.net,
Jiri Slaby <jslaby@suse.com>,
Russell King - ARM Linux admin <linux@armlinux.org.uk>,
Jason Wessel <jason.wessel@windriver.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Subject: Re: [RFC 0/5] Introduce NMI aware serial drivers
Date: Fri, 14 Aug 2020 15:18:22 +0100 [thread overview]
Message-ID: <20200814141822.opahh33nfc5yodkb@holly.lan> (raw)
In-Reply-To: <CAFA6WYPd-fcDkYNk1KrjYwD=FH3FBvjDGEoxCBBN9CRidoVXbw@mail.gmail.com>
On Fri, Aug 14, 2020 at 05:36:36PM +0530, Sumit Garg wrote:
> On Thu, 13 Aug 2020 at 15:47, Daniel Thompson
> <daniel.thompson@linaro.org> wrote:
> >
> > On Thu, Aug 13, 2020 at 02:55:12PM +0530, Sumit Garg wrote:
> > > On Thu, 13 Aug 2020 at 05:38, Doug Anderson <dianders@chromium.org> wrote:
> > > > On Wed, Aug 12, 2020 at 8:27 AM Doug Anderson <dianders@chromium.org> wrote:
> > > > > One
> > > > > last worry is that I assume that most people testing (and even
> > > > > automated testing labs) will either always enable NMI or won't enable
> > > > > NMI. That means that everyone will be only testing one codepath or
> > > > > the other and (given the complexity) the non-tested codepath will
> > > > > break.
> > > > >
> > >
> > > The current patch-set only makes this NMI to work when debugger (kgdb)
> > > is enabled which I think is mostly suitable for development
> > > environments. So most people testing will involve existing IRQ mode
> > > only.
> > >
> > > However, it's very much possible to make NMI mode as default for a
> > > particular serial driver if the underlying irqchip supports it but it
> > > depends if we really see any production level usage of NMI debug
> > > feature.
> >
> > The effect of this patch is not to make kgdb work from NMI it is to make
> > (some) SysRqs work from NMI. I think that only allowing it to deploy for
> > kgdb users is a mistake.
> >
> > Having it deploy automatically for kgdb users might be OK but it seems
> > sensible to make this feature available for other users too.
>
> I think I wasn't clear enough in my prior reply. Actually I meant to
> say that this patch-set enables NMI support for a particular serial
> driver via ".poll_init()" interface and the only current user of that
> interface is kgdb.
>
> So if there are other users interested in this feature, they can use
> ".poll_init()" interface as well to enable it.
Huh?
We appear to speaking interchangably about users (people who sit in
front of the machine and want a stack trace) and sub-systems ;-).
I don't think other SysRq commands have quite such a direct relationship
between the sub-system and the sysrq command. For example who are you
expecting to call .poll_init() if a user wants to use the SysRq to
provoke a stack trace?
Daniel.
next prev parent reply other threads:[~2020-08-14 14:18 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-21 12:10 [RFC 0/5] Introduce NMI aware serial drivers Sumit Garg
2020-07-21 12:10 ` [RFC 1/5] tty/sysrq: Make sysrq handler NMI aware Sumit Garg
2020-08-12 23:59 ` Doug Anderson
2020-08-14 7:24 ` Sumit Garg
2020-08-14 14:34 ` peterz
2020-08-14 14:57 ` Doug Anderson
2020-08-17 14:08 ` Sumit Garg
2020-08-17 17:19 ` Doug Anderson
2020-08-18 13:30 ` Sumit Garg
2020-07-21 12:10 ` [RFC 2/5] serial: core: Add framework to allow NMI aware serial drivers Sumit Garg
2020-08-12 23:59 ` Doug Anderson
2020-08-13 14:19 ` Sumit Garg
2020-08-13 14:37 ` Doug Anderson
2020-08-14 11:17 ` Sumit Garg
2020-08-14 14:13 ` Daniel Thompson
2020-08-17 12:27 ` Sumit Garg
2020-08-17 13:57 ` Doug Anderson
2020-08-17 14:23 ` Sumit Garg
2020-08-17 14:32 ` Daniel Thompson
2020-08-18 13:18 ` Sumit Garg
2020-08-17 14:28 ` Daniel Thompson
2020-08-18 13:06 ` Sumit Garg
2020-08-14 14:43 ` Doug Anderson
2020-08-17 12:29 ` Sumit Garg
2020-07-21 12:10 ` [RFC 3/5] serial: amba-pl011: Re-order APIs definition Sumit Garg
2020-07-21 12:10 ` [RFC 4/5] serial: amba-pl011: Enable NMI aware uart port Sumit Garg
2020-08-12 23:59 ` Doug Anderson
2020-08-13 10:34 ` Sumit Garg
2020-07-21 12:10 ` [RFC 5/5] serial: Remove KGDB NMI serial driver Sumit Garg
2020-08-11 13:50 ` [RFC 0/5] Introduce NMI aware serial drivers Sumit Garg
2020-08-11 13:58 ` Greg Kroah-Hartman
2020-08-11 14:29 ` Sumit Garg
2020-08-11 14:58 ` Greg Kroah-Hartman
2020-08-11 17:15 ` Doug Anderson
2020-08-12 14:52 ` Sumit Garg
2020-08-12 15:27 ` Doug Anderson
2020-08-13 0:08 ` Doug Anderson
2020-08-13 9:25 ` Sumit Garg
2020-08-13 10:17 ` Daniel Thompson
2020-08-14 12:06 ` Sumit Garg
2020-08-14 14:18 ` Daniel Thompson [this message]
2020-08-17 5:12 ` Sumit Garg
2020-08-17 9:28 ` Daniel Thompson
2020-08-17 14:12 ` Sumit Garg
2020-08-13 15:26 ` Doug Anderson
2020-08-14 12:50 ` Sumit Garg
2020-08-12 5:48 ` Sumit Garg
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=20200814141822.opahh33nfc5yodkb@holly.lan \
--to=daniel.thompson@linaro.org \
--cc=dianders@chromium.org \
--cc=gregkh@linuxfoundation.org \
--cc=jason.wessel@windriver.com \
--cc=jslaby@suse.com \
--cc=kgdb-bugreport@lists.sourceforge.net \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-serial@vger.kernel.org \
--cc=linux@armlinux.org.uk \
--cc=sumit.garg@linaro.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
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;
as well as URLs for NNTP newsgroup(s).