Re: mainline build failure due to cf21f328fcaf ("media: nxp: Add i.MX8 ISI driver")

From: Mauro Carvalho Chehab <mchehab@kernel.org>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Krzysztof Kozlowski <krzk@kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Linux regressions mailing list <regressions@lists.linux.dev>,
	"Sudip Mukherjee (Codethink)" <sudipm.mukherjee@gmail.com>,
	Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
	Shawn Guo <shawnguo@kernel.org>,
	Sascha Hauer <s.hauer@pengutronix.de>,
	NXP Linux Team <linux-imx@nxp.com>,
	linux-media@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	Pengutronix Kernel Team <kernel@pengutronix.de>,
	Fabio Estevam <festevam@gmail.com>
Subject: Re: mainline build failure due to cf21f328fcaf ("media: nxp: Add i.MX8 ISI driver")
Date: Mon, 15 May 2023 10:25:25 +0100	[thread overview]
Message-ID: <20230515102525.65150633@sal.lan> (raw)
In-Reply-To: <CAMuHMdV=b8j=X3XEBWsAghsHrPT58xp7peaMiTZisqf7wRJf3w@mail.gmail.com>

Em Mon, 15 May 2023 09:46:41 +0200
Geert Uytterhoeven <geert@linux-m68k.org> escreveu:

> Hi Krzysztof,
> 
> On Sun, May 14, 2023 at 1:01 PM Krzysztof Kozlowski <krzk@kernel.org> wrote:
> > On 10/05/2023 10:05, Mauro Carvalho Chehab wrote:  
> > > And another CI job testing bisect breakages as I receive pull requests,
> > > applying patch per patch and using both allyesconfig and allmodconfig,
> > > also on x86_64 arch with W=1:
> > >
> > >       https://builder.linuxtv.org/job/patchwork/
> > >
> > > The rule is to not merge stuff on media tree if any of those jobs
> > > fail. I also fast-forward merging patches whose subject states that
> > > the build has failed.
> > >
> > > In order to help with that, on normal situation, I usually take one week
> > > to merge stuff from media_stage into media_tree, doing rebases at
> > > media_stage if needed to avoid git bisect build breakages at media_tree
> > > (which is from where I send my update PRs to you).
> > >
> > > Unfortunately, currently we don't have resources to do multiple randconfig  
> >
> > Is you media staging tree included in LKP (kernel test robot)? You would
> > get huge build coverage after every push to your staging repo.  

No idea, as I don't know where LKP settings are stored, nor what frequency
it is doing builds from git://linuxtv.org/media_stage.git, if any. Do you know
where we can check such configuration?

In the end, patches there will end going to linux-next, so at least some
sort of coverage is there, but I'm not sure if LKP will always reply to
linux-media if the patch causing build regressions is there.

While being helpful, one problem with LKP is that it is hard to filter out 
reports per git tree. The only way to check if the report is applicable to
media trees seems to be looking inside the e-mail's body.

> As (multiple[*[) fixes for the build issues were submitted before the
> opening of the merge window, there must have been some build coverage,
> with even some people acting upon it...
> 
> [*] General note, not limited to media: please apply build fixes and
>     regression fixes ASAP, to avoid multiple people running into the
>     same issues, and spending time on bisecting, investigating,
>     fixing, ...
>     Thanks a lot!

Fully agreed. That's why we opted to have a CI instance focused on media:
we should be able to program it to give feedback with the kernel build
parameters we use (Like W=1) and set it up in a way that it we can
customize to our needs (like testing for the architectures where media
drivers are known to be used in practice), and setting up an e-mail subject
that can be easily be filtered by our e-mail filters.

Regards,
Mauro

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