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From: daniel.lezcano@linaro.org (Daniel Lezcano)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] clocksource/drivers/pistachio: Fix wrong calculated clocksource read value
Date: Tue, 15 Dec 2015 21:59:30 +0100	[thread overview]
Message-ID: <56707F32.3030405@linaro.org> (raw)
In-Reply-To: <1448466169-5230-1-git-send-email-jszhang@marvell.com>

On 11/25/2015 04:42 PM, Jisheng Zhang wrote:
> Let's assume the counter value is 0xf000000, the pistachio clocksource
> read cycles function would return 0xffffffff0fffffff, but it should
> return 0xfffffff.
>
> We fix this issue by calculating bitwise-not counter, then cast to
> cycle_t.
>
> Signed-off-by: Jisheng Zhang <jszhang@marvell.com>

Hi Jisheng,

I tried to reproduce this behavior on x86_64 but without success.

On which architecture did you produce this result ? Do you have a simple 
test program to check with ?

Thanks

   -- Daniel


-- 
  <http://www.linaro.org/> Linaro.org ? Open source software for ARM SoCs

Follow Linaro:  <http://www.facebook.com/pages/Linaro> Facebook |
<http://twitter.com/#!/linaroorg> Twitter |
<http://www.linaro.org/linaro-blog/> Blog

WARNING: multiple messages have this Message-ID (diff)
From: Daniel Lezcano <daniel.lezcano@linaro.org>
To: Jisheng Zhang <jszhang@marvell.com>, tglx@linutronix.de
Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] clocksource/drivers/pistachio: Fix wrong calculated clocksource read value
Date: Tue, 15 Dec 2015 21:59:30 +0100	[thread overview]
Message-ID: <56707F32.3030405@linaro.org> (raw)
In-Reply-To: <1448466169-5230-1-git-send-email-jszhang@marvell.com>

On 11/25/2015 04:42 PM, Jisheng Zhang wrote:
> Let's assume the counter value is 0xf000000, the pistachio clocksource
> read cycles function would return 0xffffffff0fffffff, but it should
> return 0xfffffff.
>
> We fix this issue by calculating bitwise-not counter, then cast to
> cycle_t.
>
> Signed-off-by: Jisheng Zhang <jszhang@marvell.com>

Hi Jisheng,

I tried to reproduce this behavior on x86_64 but without success.

On which architecture did you produce this result ? Do you have a simple 
test program to check with ?

Thanks

   -- Daniel


-- 
  <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs

Follow Linaro:  <http://www.facebook.com/pages/Linaro> Facebook |
<http://twitter.com/#!/linaroorg> Twitter |
<http://www.linaro.org/linaro-blog/> Blog


  reply	other threads:[~2015-12-15 20:59 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-25 15:42 [PATCH] clocksource/drivers/pistachio: Fix wrong calculated clocksource read value Jisheng Zhang
2015-11-25 15:42 ` Jisheng Zhang
2015-12-15 20:59 ` Daniel Lezcano [this message]
2015-12-15 20:59   ` Daniel Lezcano
2015-12-16  7:11   ` Jisheng Zhang
2015-12-16  7:11     ` Jisheng Zhang
2015-12-16  7:28     ` Jisheng Zhang
2015-12-16  7:28       ` Jisheng Zhang
2015-12-16  7:36       ` Jisheng Zhang
2015-12-16  7:36         ` Jisheng Zhang
2015-12-16  7:49         ` Jisheng Zhang
2015-12-16  7:49           ` Jisheng Zhang
2015-12-16  9:21         ` Daniel Lezcano
2015-12-16  9:21           ` Daniel Lezcano
2015-12-16  9:33           ` Russell King - ARM Linux
2015-12-16  9:33             ` Russell King - ARM Linux
2015-12-16 10:32             ` Daniel Lezcano
2015-12-16 10:32               ` Daniel Lezcano
2015-12-16 10:38               ` Russell King - ARM Linux
2015-12-16 10:38                 ` Russell King - ARM Linux
2015-12-16 16:23                 ` Daniel Lezcano
2015-12-16 16:23                   ` Daniel Lezcano
2015-12-17  9:07                 ` Jisheng Zhang
2015-12-17  9:07                   ` Jisheng Zhang
2015-12-16  9:01       ` Daniel Lezcano
2015-12-16  9:01         ` Daniel Lezcano
2015-12-16  9:02     ` Daniel Lezcano
2015-12-16  9:02       ` Daniel Lezcano

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