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

From: Florian Fainelli <f.fainelli@gmail.com>
To: Bjorn Helgaas <helgaas@kernel.org>,
	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: Tue, 14 Jun 2022 09:16:40 -0700	[thread overview]
Message-ID: <7b2d26e2-e4a5-b5f2-4e57-a5b102ed3f4a@gmail.com> (raw)
In-Reply-To: <20220614000052.GA727153@bhelgaas>

On 6/13/22 17:00, Bjorn Helgaas wrote:
> 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.

Humm, OK.

> 
>> - 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.

Yes, I suppose that is fair, ideally this would have been an one liner 
but it was not quite that simple.

> 
>> - 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.

Apologies accepted :)

> 
>> 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.

This is fine, I am not technically the driver author but Jim and I work 
together and I can always prioritize his work on upstream versus what we 
do downstream. As the "new" Raspberry Pi maintainer however I do care as 
well about not introducing regressions for Pi users, even if upstream is 
a niche on those platforms.

> 
> 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.
> 

OK, thanks for your response, this makes me feel better.
-- 
Florian