Re: [GIT PULL] Immutable branch between MFD, PWM and RTC due for the v5.13 merge window

From: Alexandre Belloni <alexandre.belloni@bootlin.com>
To: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: "Lee Jones" <lee.jones@linaro.org>,
	"Jonathan Neuschäfer" <j.neuschaefer@gmx.net>,
	"Heiko Stuebner" <heiko@sntech.de>,
	devicetree@vger.kernel.org,
	"Linus Walleij" <linus.walleij@linaro.org>,
	"Thierry Reding" <thierry.reding@gmail.com>,
	"Sam Ravnborg" <sam@ravnborg.org>,
	linux-rtc@vger.kernel.org, "Arnd Bergmann" <arnd@arndb.de>,
	"Mauro Carvalho Chehab" <mchehab+huawei@kernel.org>,
	"Fabio Estevam" <festevam@gmail.com>,
	"Daniel Palmer" <daniel@0x0f.com>,
	"Andy Shevchenko" <andy.shevchenko@gmail.com>,
	"Andreas Kemnade" <andreas@kemnade.info>,
	"NXP Linux Team" <linux-imx@nxp.com>,
	linux-pwm@vger.kernel.org,
	"Stephan Gerhold" <stephan@gerhold.net>,
	allen <allen.chen@ite.com.tw>,
	"Sascha Hauer" <s.hauer@pengutronix.de>,
	"Lubomir Rintel" <lkundrak@v3.sk>,
	"Mark Brown" <broonie@kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	"Alessandro Zummo" <a.zummo@towertech.it>,
	linux-kernel@vger.kernel.org, "Rob Herring" <robh+dt@kernel.org>,
	"Pengutronix Kernel Team" <kernel@pengutronix.de>,
	"Heiko Stuebner" <heiko.stuebner@theobroma-systems.com>,
	"Josua Mayer" <josua.mayer@jm0.eu>,
	"Shawn Guo" <shawnguo@kernel.org>,
	"David S. Miller" <davem@davemloft.net>
Subject: Re: [GIT PULL] Immutable branch between MFD, PWM and RTC due for the v5.13 merge window
Date: Wed, 10 Mar 2021 12:54:08 +0100	[thread overview]
Message-ID: <YEizYHPnzyLad6Yi@piout.net> (raw)
In-Reply-To: <20210310113959.dnokjrt7dos43fx6@pengutronix.de>

On 10/03/2021 12:39:59+0100, Uwe Kleine-König wrote:
> Hello Lee,
> 
> On Tue, Mar 09, 2021 at 08:05:20PM +0000, Lee Jones wrote:
> > On Mon, 01 Mar 2021, Lee Jones wrote:
> > 
> > > The following changes since commit fe07bfda2fb9cdef8a4d4008a409bb02f35f1bd8:
> > > 
> > >   Linux 5.12-rc1 (2021-02-28 16:05:19 -0800)
> > > 
> > > are available in the Git repository at:
> > > 
> > >   git://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd.git ib-mfd-pwm-rtc-v5.13
> > > 
> > > for you to fetch changes up to 80629611215d1c5d52ed3cf723fd6d24a5872504:
> > > 
> > >   MAINTAINERS: Add entry for Netronix embedded controller (2021-03-01 10:26:17 +0000)
> > > 
> > > ----------------------------------------------------------------
> > > Immutable branch between MFD, PWM and RTC due for the v5.13 merge window
> > > 
> > > ----------------------------------------------------------------
> > > [...]
> > 
> > FYI, if anyone has pulled this, they should probably rebase it onto
> > v5.12-rc2 and delete the v5.12-rc1 tag from their tree:
> > 
> >   https://lwn.net/Articles/848431/
> 
> I'm not directly affected, but I wonder: The idea of an immutable branch
> is that the same history gets included in different trees. If now each
> maintainer rebases individually the result isn't the same
> history any more in each tree which somewhat defeats the idea of using
> immutable branches.
> 
> IMHO there are two ways forward: Either someone (Lee again?) creates a
> new pull request for this series rebased on -rc2; or we accept that
> these few patches are based on -rc1. For the latter it would be
> beneficial to merge the tag into a tree that is already based on -rc2.
> 

The solution is simply for the maintainers merging the immutable branch
to do that in a branch based on -rc2. Eg. I've rebased rtc-next on -rc2
(fast forward, I didn't have any patch). I can now merge this branch if
necessary, problem solved. If you can't rebased, nothing prevents you
from merging -rc2 in any branch.

-- 
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com