From: Clemens Ladisch <clemens@ladisch.de>
To: David Rientjes <rientjes@google.com>
Cc: Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [patch v2] x86: allow ZONE_DMA to be configurable
Date: Fri, 15 Apr 2011 13:42:43 +0200 [thread overview]
Message-ID: <4DA82F33.7080403@ladisch.de> (raw)
In-Reply-To: <alpine.DEB.2.00.1104141134260.386@chino.kir.corp.google.com>
David Rientjes wrote:
> ZONE_DMA is unnecessary for a large number of machines that do not
> require addressing in the lower 16MB of memory because they do not use
> ISA devices with 16-bit address registers (plus one page byte register).
>
> This patch allows users to disable ZONE_DMA for x86 if they know they
> will not be using such devices with their kernel.
> ...
> config ZONE_DMA
> - def_bool y
> + bool "DMA memory allocation support" if EXPERT
Better call it "ISA/LPC DMA memory allocation support".
> + default y
Does it make sense to have this without CONFIG_ISA_DMA_API?
> + help
> + DMA memory allocation support allows old ISA devices with 16-bit
> + address registers to allocate memory within the first 16MB of
> + address space. Disable if no such devices will be used.
"Old ISA devices" might be misleading because ISA does not imply actual
ISA slots; please mention LPC devices like the floppy controller and the
parallel port in ECP mode.
Regards,
Clemens
next prev parent reply other threads:[~2011-04-15 11:41 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-14 18:38 [patch v2] x86: allow ZONE_DMA to be configurable David Rientjes
2011-04-15 11:42 ` Clemens Ladisch [this message]
2011-04-15 20:08 ` H. Peter Anvin
2011-04-21 2:31 ` David Rientjes
2011-04-21 4:07 ` H. Peter Anvin
2011-04-27 23:37 ` [patch v3] " David Rientjes
2011-05-04 0:00 ` David Rientjes
2011-05-04 0:20 ` H. Peter Anvin
2011-05-16 20:54 ` [patch v4] " David Rientjes
2011-05-16 20:56 ` H. Peter Anvin
2011-05-16 23:13 ` [tip:x86/mm] x86, mm: Allow " tip-bot for David Rientjes
2011-08-17 10:37 ` Borislav Petkov
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