From: Michael Ellerman <mpe@ellerman.id.au>
To: Baoquan He <bhe@redhat.com>, linux-kernel@vger.kernel.org
Cc: linux-arch@vger.kernel.org, linux-mm@kvack.org, arnd@arndb.de,
geert@linux-m68k.org, mcgrof@kernel.org, hch@infradead.org,
Baoquan He <bhe@redhat.com>,
linux-alpha@vger.kernel.org, linux-hexagon@vger.kernel.org,
linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org,
linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-sh@vger.kernel.org, sparclinux@vger.kernel.org
Subject: Re: [PATCH v3 2/2] arch/*/io.h: remove ioremap_uc in some architectures
Date: Sun, 05 Mar 2023 20:23:05 +1100 [thread overview]
Message-ID: <87sfej1rie.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <20230303102817.212148-3-bhe@redhat.com>
Baoquan He <bhe@redhat.com> writes:
> ioremap_uc() is only meaningful on old x86-32 systems with the PAT
> extension, and on ia64 with its slightly unconventional ioremap()
> behavior, everywhere else this is the same as ioremap() anyway.
>
> Here, remove the ioremap_uc() definition in architecutures other
> than x86 and ia64. These architectures all have asm-generic/io.h
> included and will have the default ioremap_uc() definition which
> returns NULL.
>
> Note: This changes the existing behaviour and could break code
> calling ioremap_uc(). If any ARCH meets this breakage and really
> needs a specific ioremap_uc() for its own usage, one ioremap_uc()
> can be added in the ARCH.
I see one use in:
drivers/video/fbdev/aty/atyfb_base.c: par->ati_regbase = ioremap_uc(info->fix.mmio_start, 0x1000);
Which isn't obviously x86/ia64 specific.
I'm pretty sure some powermacs (powerpc) use that driver.
Maybe that exact code path is only reachable on x86/ia64? But if so
please explain why.
Otherwise it looks like this series could break that driver on powerpc
at least.
cheers
next prev parent reply other threads:[~2023-03-05 9:23 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20230303102817.212148-1-bhe@redhat.com>
2023-03-03 10:28 ` [PATCH v3 2/2] arch/*/io.h: remove ioremap_uc in some architectures Baoquan He
2023-03-05 9:23 ` Michael Ellerman [this message]
2023-03-05 9:29 ` Geert Uytterhoeven
2023-03-05 20:10 ` Arnd Bergmann
2023-03-07 0:58 ` Michael Ellerman
2023-03-07 1:30 ` Baoquan He
2023-03-07 7:17 ` Arnd Bergmann
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