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From: jamie@shareable.org (Jamie Lokier)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm: remove unused code in delay.S
Date: Thu, 17 Sep 2009 20:32:57 +0100	[thread overview]
Message-ID: <20090917193257.GA10599@shareable.org> (raw)
In-Reply-To: <20090916134721.GA11218@n2100.arm.linux.org.uk>

Russell King - ARM Linux wrote:
> On Tue, Sep 15, 2009 at 11:04:37PM +0200, Krzysztof Halasa wrote:
> > Steve Chen <schen@mvista.com> writes:
> > 
> > > +config OLD_CPU_DELAY
> > > +	depends on CPU_32v3 || CPU_32v4 || CPU_32v4T
> > > +	bool "Accurate delays"
> > > +	def_bool n
> > > +	help
> > > +	  Enable if observing longer than expected delays and need more
> > > +	  accuracy.  This only applies to older CPUs.
> > > +
> > 
> > If it's that simple then why not enable the extra delay code
> > unconditionally when compiling for those CPUs?
> 
> Because it's really not that clear cut.  Eg, ARM610 and ARM710 work
> better with it, but StrongARM suffers from delays being too short.
> Having a kernel configured for all those processors used to be common
> (since the Acorn RiscPC had pluggable CPU cards, which could be one
> of those processors.)
> 
> It's really something that only experienced people should worry
> about, and not Joe "kernel-builder" Bloggs.

I'm confused now.  If I'm building a "generic" kernel to run on
several different systems, including some ARM710s and some StrongARMs,
do I include the code or not?

Btw, do you know where PT110 fits in?  Is it like StrongARM (SA110)?

Thanks,
-- Jamie

WARNING: multiple messages have this Message-ID (diff)
From: Jamie Lokier <jamie@shareable.org>
To: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: Krzysztof Halasa <khc@pm.waw.pl>, Steve Chen <schen@mvista.com>,
	Felipe Contreras <felipe.contreras@gmail.com>,
	linux-kernel@vger.kernel.org, Marek Vasut <marek.vasut@gmail.com>,
	Pavel Machek <pavel@ucw.cz>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] arm: remove unused code in delay.S
Date: Thu, 17 Sep 2009 20:32:57 +0100	[thread overview]
Message-ID: <20090917193257.GA10599@shareable.org> (raw)
In-Reply-To: <20090916134721.GA11218@n2100.arm.linux.org.uk>

Russell King - ARM Linux wrote:
> On Tue, Sep 15, 2009 at 11:04:37PM +0200, Krzysztof Halasa wrote:
> > Steve Chen <schen@mvista.com> writes:
> > 
> > > +config OLD_CPU_DELAY
> > > +	depends on CPU_32v3 || CPU_32v4 || CPU_32v4T
> > > +	bool "Accurate delays"
> > > +	def_bool n
> > > +	help
> > > +	  Enable if observing longer than expected delays and need more
> > > +	  accuracy.  This only applies to older CPUs.
> > > +
> > 
> > If it's that simple then why not enable the extra delay code
> > unconditionally when compiling for those CPUs?
> 
> Because it's really not that clear cut.  Eg, ARM610 and ARM710 work
> better with it, but StrongARM suffers from delays being too short.
> Having a kernel configured for all those processors used to be common
> (since the Acorn RiscPC had pluggable CPU cards, which could be one
> of those processors.)
> 
> It's really something that only experienced people should worry
> about, and not Joe "kernel-builder" Bloggs.

I'm confused now.  If I'm building a "generic" kernel to run on
several different systems, including some ARM710s and some StrongARMs,
do I include the code or not?

Btw, do you know where PT110 fits in?  Is it like StrongARM (SA110)?

Thanks,
-- Jamie


  reply	other threads:[~2009-09-17 19:32 UTC|newest]

Thread overview: 80+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-09-13 21:05 [PATCH] arm: remove unused code in delay.S Felipe Contreras
2009-09-13 21:05 ` Felipe Contreras
2009-09-13 21:28 ` Marek Vasut
2009-09-13 21:28   ` Marek Vasut
2009-09-13 23:00   ` Russell King - ARM Linux
2009-09-13 23:00     ` Russell King - ARM Linux
2009-09-14  0:21     ` Jamie Lokier
2009-09-14  0:21       ` Jamie Lokier
2009-09-14  8:10       ` Russell King - ARM Linux
2009-09-14  8:10         ` Russell King - ARM Linux
2009-09-14 12:58         ` Felipe Contreras
2009-09-14 12:58           ` Felipe Contreras
2009-09-14 14:00           ` Russell King - ARM Linux
2009-09-14 14:00             ` Russell King - ARM Linux
2009-09-14 14:38             ` Felipe Contreras
2009-09-14 14:38               ` Felipe Contreras
2009-09-14 14:40               ` Russell King - ARM Linux
2009-09-14 14:40                 ` Russell King - ARM Linux
2009-09-14 15:14                 ` Felipe Contreras
2009-09-14 15:14                   ` Felipe Contreras
2009-09-14 15:21                   ` Russell King - ARM Linux
2009-09-14 15:21                     ` Russell King - ARM Linux
2009-09-14 15:50                     ` Felipe Contreras
2009-09-14 15:50                       ` Felipe Contreras
2009-09-14 16:25                       ` Marek Vasut
2009-09-14 16:25                         ` Marek Vasut
2009-09-14 16:54                         ` Felipe Contreras
2009-09-14 16:54                           ` Felipe Contreras
2009-09-14 15:36                   ` Wolfram Sang
2009-09-14 15:36                     ` Wolfram Sang
2009-09-14 16:06                     ` Felipe Contreras
2009-09-14 16:06                       ` Felipe Contreras
2009-09-14 16:24                       ` Wolfram Sang
2009-09-14 16:24                         ` Wolfram Sang
2009-09-15 10:37                   ` Pavel Machek
2009-09-15 10:37                     ` Pavel Machek
2009-09-15 10:47                     ` Felipe Contreras
2009-09-15 10:47                       ` Felipe Contreras
2009-09-15 10:49                       ` Pavel Machek
2009-09-15 10:49                         ` Pavel Machek
2009-09-15 11:20                         ` Felipe Contreras
2009-09-15 11:20                           ` Felipe Contreras
2009-09-15 12:29                     ` Steve Chen
2009-09-15 12:29                       ` Steve Chen
2009-09-15 13:41                       ` Marek Vasut
2009-09-15 13:41                         ` Marek Vasut
2009-09-15 16:30                         ` Steve Chen
2009-09-15 16:30                           ` Steve Chen
2009-09-15 18:58                           ` Felipe Contreras
2009-09-15 18:58                             ` Felipe Contreras
2009-09-15 19:44                             ` Steve Chen
2009-09-15 19:44                               ` Steve Chen
2009-09-15 20:39                               ` Marek Vasut
2009-09-15 20:39                                 ` Marek Vasut
2009-09-15 21:04                               ` Krzysztof Halasa
2009-09-15 21:04                                 ` Krzysztof Halasa
2009-09-15 22:26                                 ` Steve Chen
2009-09-15 22:26                                   ` Steve Chen
2009-09-15 22:47                                   ` Krzysztof Halasa
2009-09-15 22:47                                     ` Krzysztof Halasa
2009-09-16  8:26                                     ` Steve Chen
2009-09-16  8:26                                       ` Steve Chen
2009-09-16 12:30                                       ` Krzysztof Halasa
2009-09-16 12:30                                         ` Krzysztof Halasa
2009-09-16 14:49                                         ` Steve Chen
2009-09-16 14:49                                           ` Steve Chen
2009-09-16 20:21                                           ` Sergei Shtylyov
2009-09-16 20:21                                             ` Sergei Shtylyov
2009-09-16 13:47                                 ` Russell King - ARM Linux
2009-09-16 13:47                                   ` Russell King - ARM Linux
2009-09-17 19:32                                   ` Jamie Lokier [this message]
2009-09-17 19:32                                     ` Jamie Lokier
2009-09-17 19:41                                     ` Russell King - ARM Linux
2009-09-17 19:41                                       ` Russell King - ARM Linux
2009-09-17 21:29                                       ` [PATCH v2] " Steve Chen
2009-09-17 21:29                                         ` Steve Chen
2009-09-17 21:37                                         ` Jamie Lokier
2009-09-17 21:37                                           ` Jamie Lokier
2009-09-17 22:25                                           ` Steve Chen
2009-09-17 22:25                                             ` Steve Chen

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