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Date: Mon, 17 Jan 2005 17:59:38 +0100
From: "Kevin D. Kissell" <kevink@mips.com>
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To: Yoichi Yuasa <yuasa@hh.iij4u.or.jp>
CC: Ralf Baechle <ralf@linux-mips.org>,
	linux-mips <linux-mips@linux-mips.org>
Subject: Re: [PATCH 2.6.11-rc1] add local_irq_enable() to cpu_idle()
References: <20050118014958.1d9e484e.yuasa@hh.iij4u.or.jp>
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There have been times when having local_irq_enable() in my idle loop
would have prevented a hang in some of my experimental kernels, too,
but it's always been because I had screwed up somewhere else and
forgotten to re-enable interrupts.  Is there some good reason why
the kernel should end up in idle with interrupts turned off?

		Regards,

		Kevin K.

Yoichi Yuasa wrote:
> Hi Ralf,
> 
> We need to add local_irq_enable() to cpu_idle().
> Please add this patch to v2.6.
> 
> I don't have any information about R3081.
> I didn't fix r3081_wait().
> 
> Yoichi
> 
> Signed-off-by: Yoichi Yuasa <yuasa@hh.iij4u.or.jp>
> 
> diff -urN -X dontdiff a-orig/arch/mips/kernel/cpu-probe.c a/arch/mips/kernel/cpu-probe.c
> --- a-orig/arch/mips/kernel/cpu-probe.c	Sun Oct 31 21:49:07 2004
> +++ a/arch/mips/kernel/cpu-probe.c	Tue Jan 18 00:26:12 2005
> @@ -42,10 +42,12 @@
>  {
>  	unsigned long cfg = read_c0_conf();
>  	write_c0_conf(cfg | TX39_CONF_HALT);
> +	local_irq_enable();
>  }
>  
>  static void r4k_wait(void)
>  {
> +	local_irq_enable();
>  	__asm__(".set\tmips3\n\t"
>  		"wait\n\t"
>  		".set\tmips0");
> @@ -61,6 +63,7 @@
>  
>  void au1k_wait(void)
>  {
> +	local_irq_enable();
>  #ifdef CONFIG_PM
>  	/* using the wait instruction makes CP0 counter unusable */
>  	__asm__(".set\tmips3\n\t"
> diff -urN -X dontdiff a-orig/arch/mips/kernel/process.c a/arch/mips/kernel/process.c
> --- a-orig/arch/mips/kernel/process.c	Sat Jan  8 23:19:16 2005
> +++ a/arch/mips/kernel/process.c	Mon Jan 17 21:43:08 2005
> @@ -58,6 +58,8 @@
>  		while (!need_resched())
>  			if (cpu_wait)
>  				(*cpu_wait)();
> +			else
> +				local_irq_enable();
>  		schedule();
>  	}
>  }
>