From: Christoph Hellwig <hch@infradead.org>
To: Andreas Larsson <andreas@gaisler.com>
Cc: Arnd Bergmann <arnd@arndb.de>, Sam Ravnborg <sam@ravnborg.org>,
"Maciej W. Rozycki" <macro@orcam.me.uk>,
sparclinux@vger.kernel.org, Randy Dunlap <rdunlap@infradead.org>,
Miquel Raynal <miquel.raynal@bootlin.com>,
linux-parport@lists.infradead.org,
"David S . Miller" <davem@davemloft.net>,
linux-kernel@vger.kernel.org, Takashi Iwai <tiwai@suse.de>,
iommu@lists.linux.dev, linux-kbuild@vger.kernel.org,
Masahiro Yamada <masahiroy@kernel.org>
Subject: Re: [PATCH v2 4/7] sparc32: Do not select ZONE_DMA
Date: Wed, 6 Mar 2024 07:04:38 -0800 [thread overview]
Message-ID: <ZeiGBuMN_I9V94Mx@infradead.org> (raw)
In-Reply-To: <bc33b608-e0b5-4dff-aa05-8513dce409b3@gaisler.com>
On Wed, Mar 06, 2024 at 03:19:52PM +0100, Andreas Larsson wrote:
> > I think that is the correct thing to do then: the only
> > drivers that I see with this dependency are PCI sound cards
> > that apparently rely on DMA to the 16MB ISA range, which is
> > not provided by sparc.
>
> The ZONE_DMA dependency does not seem related to ISA per se. Commit
> 80ab8eae70e5 ("ALSA: Enable CONFIG_ZONE_DMA for smaller PCI DMA masks")
> that started to introduce it did were about ensuring 32-bit masks.
Yikes! That commit is just unbelievable buggy. CONFIG_ZONE_DMA
is only for architetures to select, not drivers. A driver randomly
enabling such an arch zone is just crazy.
I've been wondering for a while if we need some Kconfig magic
so that certain symbols can only be select from arch/* and not
elsewhere to prevent this (we had a few other similar cases like
DMA_MAP_OPS).
next parent reply other threads:[~2024-03-06 15:04 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20240224-sam-fix-sparc32-all-builds-v2-0-1f186603c5c4@ravnborg.org>
[not found] ` <20240224-sam-fix-sparc32-all-builds-v2-4-1f186603c5c4@ravnborg.org>
[not found] ` <8d5780f5-1047-48d7-a9c9-09b95c7b5604@gaisler.com>
[not found] ` <5648dca0-4853-4dfb-91cf-282a656beb1e@app.fastmail.com>
[not found] ` <bc33b608-e0b5-4dff-aa05-8513dce409b3@gaisler.com>
2024-03-06 15:04 ` Christoph Hellwig [this message]
2024-03-06 15:24 ` [PATCH v2 4/7] sparc32: Do not select ZONE_DMA Arnd Bergmann
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