Re: [Buildroot] [PATCH v9 06/11] board/ti/am62x_sk|am64x_sk: switch to TI SDK v8.6 sources

From: Peter Korsgaard <peter@korsgaard.com>
To: Arnout Vandecappelle <arnout@mind.be>
Cc: Romain Naour <romain.naour@smile.fr>,
	buildroot@buildroot.org,
	"Yann E. MORIN" <yann.morin.1998@free.fr>,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
	Andreas Dannenberg <dannenberg@ti.com>
Subject: Re: [Buildroot] [PATCH v9 06/11] board/ti/am62x_sk|am64x_sk: switch to TI SDK v8.6 sources
Date: Sun, 25 Jun 2023 21:14:27 +0200	[thread overview]
Message-ID: <87v8fbnylo.fsf@48ers.dk> (raw)
In-Reply-To: <1383cf3a-fa81-75b7-1e3f-45a82ebb4c7d@mind.be> (Arnout Vandecappelle's message of "Sun, 25 Jun 2023 20:59:01 +0200")

>>>>> "Arnout" == Arnout Vandecappelle <arnout@mind.be> writes:

Hi,

 >> Correct, but given the poor quality of most vendor kernels, using a
 >> board with mainline is typically a lot nicer (if the IP blocks you care
 >> about are supported naturally).

 >  I'm not sure that you can claim most vendor kernels are poor
 >  quality. At least NXP and Microchip have decent vendor
 > kernels. Conversely, when vendor kernels are horrible, mainline is
 > often not super usable either (because, of course, those vendors don't
 > invest in upstreaming either).

Sure, not all vendor kernels are equal, but vendor drivers are often
written by people not very familiar with the subsystem, so things get
handled in "odd ways", and as they have not been submitted upstream they
don't get any review feedback to clean it up. The vendor kernels of high
quality is typically the ones where the vendor developers interact with
mainline (so their drivers get reviewed by the subsystem maintainers).
E.G. for the Microchip and NXP cases, the basics are anyway in mainline,
so it is normal that the identical parts in the vendor kernel also looks
sensible.

I am not aware of any situations where the mainline kernel is of lower
quality than the vendor kernel. It will often have less features, but the
support that is there is often cleaner.

 >> Same about the support, E.G. we had issues with various vendor
 >> kernels/bootloaders breaking with newer toolchain versions.
 >> 
 >> >  That said, I think for each board we should look at what the vendor
 >> >  kernel really brings. If everything, including GPU, is working with
 >> > the upstream kernel, it doesn't make sense to use the vendor kernel. I
 >> > don't know if that's the case in this specific situation.
 >> >  Yann, Peter, Romain, Thomas, what do you think?

 >> Agreed. I would in general say go for mainline, unless there is no
 >> decent support in mainline. I would not necessarily think that GPU
 >> support is a requirement, but at least the things used by the defconfig
 >> (E.G. storage, serial, network).

 >  That's exactly the opposite of what I was saying, so not agreed I guess :-)

I guess it is a question of glass half full vs half empty. You wrote
".. we should look at what the vendor kernel really brings. If
everything, including GPU, is working with the upsteam kernel, it
doesn't make sense to use the vendor kernel", which I agreed with,
EXCEPT that I think the cutoff point should be lower than "everything
supported", but just if mainline is suitable for booting a Buildroot
defconfig, E.G. working serial/storage/network.

But like usual, this is largely up to the person contributing the
defconfig.

-- 
Bye, Peter Korsgaard
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