From: santosh.shilimkar@ti.com (Santosh Shilimkar)
To: linux-arm-kernel@lists.infradead.org
Subject: Duration of mdelay and udelay depends on MPU frequency in SMP
Date: Thu, 12 May 2011 12:12:32 +0530 [thread overview]
Message-ID: <4DCB8158.8060507@ti.com> (raw)
In-Reply-To: <BANLkTimVPnzMCL=NMb7hDkL97nJ=XdFExw@mail.gmail.com>
On 5/5/2011 12:23 PM, Saquib wrote:
> Hi All,
>
> Can anyone please help me to understand and fix this issue?
>
> When CPU frequency is "1008MHz", duration of delay was close to
> theoretical value, however, when "300MHz", it was close to about 4 times
> the theoretical value.
>
> I tested it on OMAP4(SMP) blaze board.
>
It's a well known problem if the udelay() is based of global lpj.
You can read more here [1]
Regards
Santosh
[1] http://eeek.borgchat.net/lists/arm-kernel/msg120702.html
next prev parent reply other threads:[~2011-05-12 6:42 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-05 6:49 Duration of mdelay and udelay depends on MPU frequency in SMP Saquib
2011-05-05 6:53 ` Saquib
2011-05-12 6:42 ` Santosh Shilimkar [this message]
2011-06-10 22:19 ` Menon, Nishanth
2011-06-10 22:19 ` Menon, Nishanth
2011-06-14 3:24 ` Stephen Boyd
2011-06-14 3:24 ` Stephen Boyd
2011-06-14 4:19 ` Menon, Nishanth
2011-06-14 4:19 ` Menon, Nishanth
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