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Re: Wait for two clock ticks

To: Asim <linkasim@xxxxxxxxx>
Subject: Re: Wait for two clock ticks
From: Greg Freemyer <greg.freemyer@xxxxxxxxx>
Date: Fri, 6 Mar 2009 10:08:13 -0500
Cc: Henrik Austad <henrik@xxxxxxxxx>, kernelnewbies@xxxxxxxxxxxx
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On Fri, Mar 6, 2009 at 9:59 AM, Asim <linkasim@xxxxxxxxx> wrote:
> Yes - Actually I need to wait for a device to finish something after
> which I(device) error out. Ideally, I would like a simple
> function using the standard apis that works on most kernels. I cannot
> use jiffies as I mentioned earlier. Still working on it.
>
> -Asim

In general the idea of waiting 2 whole ticks with interrupts disabled
is such a bad idea that I don't think you will find a pre-existing API
to do that.

You definitely will not be able to simply check a variable because
with interrupts disabled, their is no one to update the variable.

If you really need this, you will likely need a call into a routine
the gets the current time from a hardware clock.

IMHO, such misbehaving code will never get into mainline and is not
even a good learning experience.

Greg
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Follow-Ups:
- Re: Wait for two clock ticks
  - From: Raz

References:
- Wait for two clock ticks
  - From: Asim
- Re: Wait for two clock ticks
  - From: Henrik Austad
- Re: Wait for two clock ticks
  - From: Asim

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