Re: [PATCH v1] serdev: Set fwnode for serdev devices

From: Saravana Kannan <saravanak@google.com>
To: Florian Fainelli <f.fainelli@gmail.com>
Cc: Stefan Wahren <stefan.wahren@i2se.com>,
	Rob Herring <robh@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jiri Slaby <jirislaby@kernel.org>,
	kernel-team@android.com, linux-serial@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1] serdev: Set fwnode for serdev devices
Date: Thu, 2 Mar 2023 10:07:00 -0800	[thread overview]
Message-ID: <CAGETcx_crW9BJmUoVJv1iU-KTr+9WPp_bpfrKoxzQiJGpqDgAA@mail.gmail.com> (raw)
In-Reply-To: <faad8810-7aa4-e122-f497-73553feb8bcd@gmail.com>

On Thu, Mar 2, 2023 at 9:51 AM Florian Fainelli <f.fainelli@gmail.com> wrote:
>
>
>
> On 3/2/2023 9:20 AM, Saravana Kannan wrote:
> > On Thu, Mar 2, 2023 at 9:01 AM Stefan Wahren <stefan.wahren@i2se.com> wrote:
> >>
> >> Hi Saravana,
> >>
> >> Am 02.03.23 um 03:35 schrieb Saravana Kannan:
> >>> This allow fw_devlink to do dependency tracking for serdev devices.
> >>>
> >>> Reported-by: Florian Fainelli <f.fainelli@gmail.com>
> >>> Link: https://lore.kernel.org/lkml/03b70a8a-0591-f28b-a567-9d2f736f17e5@gmail.com/
> >>> Cc: Stefan Wahren <stefan.wahren@i2se.com>
> >>> Signed-off-by: Saravana Kannan <saravanak@google.com>
> >>
> >> since this fixes an issue on Raspberry Pi 4, shouldn't this be mentioned
> >> in the commit message and providing a Fixes tag?
> >
> > So RPi 4 was never creating a device links between serdev devices and
> > their consumers. The error message was just a new one I added and we
> > are noticing and catching the fact that serdev wasn't setting fwnode
> > for a device.
> >
> > I'm also not sure if I can say this commit "Fixes" an issue in serdev
> > core because when serdev core was written, fw_devlink wasn't a thing.
> > Once I add Fixes, people will start pulling this into stable
> > branches/other trees where I don't think this should be pulled into
> > older stable branches.
>
> That is kind of the point of Fixes: tag, is not it? It is appropriate to
> list a commit that is not specific to serdev, but maybe a particular
> point into the fw_devlink history.

I don't want to pick an arbitrary point in fw_devlink as I don't want
people picking this up with some old version of fw_devlink and having
to support it there.

> Given this did not appear to have a
> functional impact, we could go without one.

This is my take too.

Greg/Rob,

If you really want a Fixes here, can you please just add it instead of
a v2 patch just for that? You can use this commit:
3fb16866b51d driver core: fw_devlink: Make cycle detection more robust

-Saravana