Re: [PATCH] asm-generic: Raise default NR_IRQS when using sparse IRQs

[Thomas Gleixner <tglx@linutronix.de>]

On Wed, 24 Nov 2010, Mark Brown wrote:

> Rather than have each platform using sparse IRQs pick a suitably large
> NR_IRQS for use with sparse IRQs make the default exceptionally high
> when they are enabled.
> 
> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
> ---
>  include/asm-generic/irq.h |    6 +++++-
>  1 files changed, 5 insertions(+), 1 deletions(-)
> 
> diff --git a/include/asm-generic/irq.h b/include/asm-generic/irq.h
> index b90ec0b..a76bea2 100644
> --- a/include/asm-generic/irq.h
> +++ b/include/asm-generic/irq.h
> @@ -4,11 +4,15 @@
>  /*
>   * NR_IRQS is the upper bound of how many interrupts can be handled
>   * in the platform. It is used to size the static irq_map array,
> - * so don't make it too big.
> + * so don't make it too big unless we're using sparse IRQs.
>   */
>  #ifndef NR_IRQS
> +#ifdef CONFIG_SPARSE_IRQ
> +#define NR_IRQS 0x7fffffff

Resulting in a 256 MB bitmap. I guess you did not try to boot that on
some random ARM board :)

Thanks,

	tglx