From: Stephen Boyd <sboyd@codeaurora.org>
To: Will Deacon <will.deacon@arm.com>
Cc: Russell King <linux@arm.linux.org.uk>,
Daniel Walker <dwalker@codeaurora.org>,
Nicolas Pitre <nico@fluxnic.net>,
Kevin Hilman <khilman@deeprootsystems.com>,
linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
Saravana Kannan <skannan@codeaurora.org>,
Santosh Shilimkar <santosh.shilimkar@ti.com>,
Colin Cross <ccross@android.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCHv2 1/3] ARM: Translate delay.S into (mostly) C
Date: Wed, 03 Nov 2010 16:15:03 -0700 [thread overview]
Message-ID: <4CD1ECF7.5030105@codeaurora.org> (raw)
In-Reply-To: <1288808841.23615.5.camel@e102144-lin.cambridge.arm.com>
On 11/03/2010 11:27 AM, Will Deacon wrote:
> Hi Stephen,
>
> On Thu, 2010-10-28 at 21:19 +0000, Stephen Boyd wrote:
>> Nico expressed concern that fixed lpj cmdlines will break due to
>> compiler optimizations. That doesn't seem to be the case since
>> before and after this patch I get the same lpj value when running
>> my CPU at 19.2 MHz. That should be sufficiently slow enough to
>> cover any machine running Linux.
>
> I appreciate this is an exceptional case, but there are some lucky
> guys at ARM who (as routinely as they can) boot Linux on sub 1MHz
> hardware. The delay loop is something they're keen to avoid so they do
> make use of the lpj= command line option and would rather it didn't
> break on them.
Do you know if it breaks at that frequency? I don't have any hardware to
test with that goes lower than the stated 19.2 MHz.
--
Sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
WARNING: multiple messages have this Message-ID (diff)
From: sboyd@codeaurora.org (Stephen Boyd)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCHv2 1/3] ARM: Translate delay.S into (mostly) C
Date: Wed, 03 Nov 2010 16:15:03 -0700 [thread overview]
Message-ID: <4CD1ECF7.5030105@codeaurora.org> (raw)
In-Reply-To: <1288808841.23615.5.camel@e102144-lin.cambridge.arm.com>
On 11/03/2010 11:27 AM, Will Deacon wrote:
> Hi Stephen,
>
> On Thu, 2010-10-28 at 21:19 +0000, Stephen Boyd wrote:
>> Nico expressed concern that fixed lpj cmdlines will break due to
>> compiler optimizations. That doesn't seem to be the case since
>> before and after this patch I get the same lpj value when running
>> my CPU at 19.2 MHz. That should be sufficiently slow enough to
>> cover any machine running Linux.
>
> I appreciate this is an exceptional case, but there are some lucky
> guys at ARM who (as routinely as they can) boot Linux on sub 1MHz
> hardware. The delay loop is something they're keen to avoid so they do
> make use of the lpj= command line option and would rather it didn't
> break on them.
Do you know if it breaks at that frequency? I don't have any hardware to
test with that goes lower than the stated 19.2 MHz.
--
Sent by an employee of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
next prev parent reply other threads:[~2010-11-03 23:15 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-28 21:19 [PATCHv2 0/3] ARM: Fixing udelay() for SMP and non-SMP systems Stephen Boyd
2010-10-28 21:19 ` Stephen Boyd
2010-10-28 21:19 ` [PATCHv2 1/3] ARM: Translate delay.S into (mostly) C Stephen Boyd
2010-10-28 21:19 ` Stephen Boyd
2010-11-03 17:57 ` Daniel Walker
2010-11-03 17:57 ` Daniel Walker
2010-11-04 2:40 ` Nicolas Pitre
2010-11-04 2:40 ` Nicolas Pitre
2010-11-03 18:27 ` Will Deacon
2010-11-03 18:27 ` Will Deacon
2010-11-03 23:15 ` Stephen Boyd [this message]
2010-11-03 23:15 ` Stephen Boyd
2010-11-03 23:17 ` Daniel Walker
2010-11-03 23:17 ` Daniel Walker
2010-10-28 21:19 ` [PATCHv2 2/3] ARM: Allow machines to override __delay() Stephen Boyd
2010-10-28 21:19 ` Stephen Boyd
2010-11-04 19:30 ` Daniel Walker
2010-11-04 19:30 ` Daniel Walker
2010-11-04 20:58 ` Stephen Boyd
2010-11-04 20:58 ` Stephen Boyd
2010-11-04 21:16 ` Daniel Walker
2010-11-04 21:16 ` Daniel Walker
2010-11-05 21:51 ` Stephen Boyd
2010-11-05 21:51 ` Stephen Boyd
2010-11-05 23:43 ` Daniel Walker
2010-11-05 23:43 ` Daniel Walker
2010-11-06 3:36 ` Stephen Boyd
2010-11-06 3:36 ` Stephen Boyd
2010-11-08 18:11 ` Daniel Walker
2010-11-08 18:11 ` Daniel Walker
2010-10-28 21:19 ` [PATCHv2 3/3] ARM: Implement a timer based __delay() loop Stephen Boyd
2010-10-28 21:19 ` Stephen Boyd
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