Re: [PATCH] HVC: do not request the irq twice.

[Christian Borntraeger <borntraeger@de.ibm.com>]

Am Thursday 22 January 2009 18:56:08 schrieb Ian Campbell:
> --- a/drivers/char/hvc_irq.c
> +++ b/drivers/char/hvc_irq.c
> @@ -28,6 +28,10 @@ int notifier_add_irq(struct hvc_struct *hp, int irq)
>  		hp->irq_requested = 0;
>  		return 0;
>  	}
> +
> +	if (hp->irq_requested)
> +		return 0;
> +
>  	rc = request_irq(irq, hvc_handle_interrupt, IRQF_DISABLED,
>  			   "hvc_console", hp);
>  	if (!rc)

Unfortunately I have no system with an irq based hvc console - I cannot test 
this patch. Anyway, the patch looks sane:

Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>

If this really fixes a problem, I am asking myself, if notifier_del can be 
called several times as well. If yes, it might be better to call free_irq at 
the last notifier_del - which means we need proper refcounting. Otherwise the 
console switches into polling mode....

Christian, blaming Rusty for using hvc_console in virtio_console which made me 
somehow responsible for this code...  ;-)