Re: [PATCH 0/4] PCI: brcmstb: Revert subdevice regulator stuff

From: Bjorn Helgaas <helgaas@kernel.org>
To: Florian Fainelli <f.fainelli@gmail.com>
Cc: Jim Quinlan <jim2101024@gmail.com>,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Cyril Brulebois <kibi@debian.org>,
	Nicolas Saenz Julienne <nsaenz@kernel.org>,
	bcm-kernel-feedback-list@broadcom.com, linux-pci@vger.kernel.org,
	regressions@lists.linux.dev, Bjorn Helgaas <bhelgaas@google.com>
Subject: Re: [PATCH 0/4] PCI: brcmstb: Revert subdevice regulator stuff
Date: Mon, 13 Jun 2022 19:00:52 -0500	[thread overview]
Message-ID: <20220614000052.GA727153@bhelgaas> (raw)
In-Reply-To: <e58125a4-f885-ae55-0441-d52ecab9a1e8@gmail.com>

On Mon, Jun 13, 2022 at 10:06:12AM -0700, Florian Fainelli wrote:
> On 5/11/22 13:39, Bjorn Helgaas wrote:
> > On Wed, May 11, 2022 at 01:24:55PM -0700, Florian Fainelli wrote:
> > > On 5/11/22 13:18, Bjorn Helgaas wrote:
> > > > From: Bjorn Helgaas <bhelgaas@google.com>
> > > > 
> > > > Cyril reported that 830aa6f29f07 ("PCI: brcmstb: Split brcm_pcie_setup()
> > > > into two funcs"), which appeared in v5.17-rc1, broke booting on the
> > > > Raspberry Pi Compute Module 4.  Revert 830aa6f29f07 and subsequent patches
> > > > for now.
> > > 
> > > How about we get a chance to fix this? Where, when and how was this even
> > > reported?
> > 
> > Sorry, I forgot to cc you, that's my fault:
> >    https://lore.kernel.org/r/CABhMZUWjZCwK1_qT2ghTSu2dguJBzBTpiTqKohyA72OSGMsaeg@mail.gmail.com
> > 
> > If you come up with a fix, I'll drop the reverts, of course.

> What is even better is that meanwhile there was already a candidate fix
> proposed on May 18th, and a v2 on May 28th, so still an alternative to the
> reverts making it to Linus' tree, or so I thought.

I hoped for a fix, but neither of those seemed to be clearly better.

> - the history for pcie-brcmstb.c is now looking super ugly because we have 4
> commits getting reverted and if we were to add back the original feature
> being added now what? Do we come up with reverts of reverts, or the modified
> (with the fix) original commits applied on top, are not we going to sign
> ourselves for another 13 or so round of patches before we all agree on the
> solution?

I agree on the ugliness and I try hard to avoid that.  In this case I
waited too long after the regression was discovered, hoping for a fix
that was better than the revert.  And I should have asked for
trade-offs between the revert and the the CM4 regression.

> - we could have just fixed this with proper communication from the get go
> about the regression in the first place, which remains the failure in
> communicating appropriately with driver authors/maintainers

I apologized earlier for omitting you when the regression was
discovered, and I'm still sorry.

> I appreciate that as a maintainer you are very sensitive to regressions and
> want to be responsive and responsible but this is not leaving just a
> slightest chance to right a wrong. Can we not do that again please?

Cyril opened the bugzilla April 30 and I forwarded it to linux-pci and
to Jim (but not you; again, I'm sorry for that omission) on May 2.
From my perspective we had almost a month to push this forward, but we
didn't quite make it.

I posted the reverts May 11, but I did not realize the regression to
you and other users they would cause.  I apologize for that.

Bjorn