Subject: Re: cardbus code without busy wait
To: Hayakawa Koichi <>
From: Lennart Augustsson <>
List: tech-kern
Date: 01/19/2000 10:45:33
Hayakawa Koichi wrote:

> From: Lennart Augustsson <>
> Subject: Re: cardbus code without busy wait
> Date: Wed, 19 Jan 2000 09:56:58 +0100
> Message-ID: <>
>  > Hayakawa Koichi wrote:
>  >
>  > > This code is not beautiful, because in interrupt context we
>  > > must use busy wait.  Unfortunately, PCcard probe routine may
>  > > be called in interrupt context.
>  >
>  > Why?  If the probe is called from an interrupt context then there should
>  > be another thread for it.
> Oh, I made a mistake...  I worry about card attaching
> sequence at boot time.  At boot time, kernel thread cannot
> be used when inserted device is used to boot kernel up.
> Which context is used during the boot sequence?

Oh, OK.  Yes, if you want to be able to attach at boot time you need
to busy wait.  But that can be hidden away in some wait routine that
checks for the `cold' variable.
You can also delay attaching until the attach thread is running.  I thought
that was what the cardbus code did already?  Unless you give `flag 1' on
in the config file.  I stole this idea for the USB code. :)


        -- Lennart