From linux-arm-kernel  Mon May 23 15:23:17 2005
From: Matthias Welwarsky <mwelwarsky () web ! de>
Date: Mon, 23 May 2005 15:23:17 +0000
To: linux-arm-kernel
Subject: Re: interrupt from interrupt
Message-Id: <200505231723.17266.mwelwarsky () web ! de>
X-MARC-Message: https://marc.info/?l=linux-arm-kernel&m=111686195312537

On Monday 23 May 2005 09:37, Thomas Surrel wrote:
> Hi,
>
> I'm using a 2.4.27 kernel on a AT91RM9200.
> I'm trying to trigger a SPI tranfer when i receive an interrupt on a
> port. But i get a "Scheduling in interrupt" error if i do this on the
> interrupt routine, or in a tasklet.
>
> I guess the problem is that the SPI transfert uses interrupts itself, as
> it calls wait_on_completion() at the start of the transfer, and
> complete() in an interrupt routine.

You cannot do wait_on_completion() from an interrupt, it might sleep.

> So, what mechanism would allow me to trigger a function involving
> interrupts from an interrupt routine ?

A kernel thread sleeping on a request queue, being woken up from the from the 
interrupt service.

>
> Thanks in advance for any help !
>
> Thomas
>
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