Re: UART IRQ over SMP

On Mon, Mar 04, 2013 at 11:18:53AM +0200, Noam Camus wrote:

Hello 

I got my UART IRQ line hardwired to CPU0. 
However CPU1 (due to scheduler balancing I presume) is used for calling the request_irq() from 8250.c.
By doing that the "chip" irq_enable() is unmasking UART IRQ line of CPU1 and not CPU0.
Now I do not get UART interrupts since they are masked at CPU0.

I tried to unmask CPU0 UART IRQ line by default at early boot.
Once I do that I get some spurious interrupt that handle_level_irq() leaves masked.
It is because I did not register any action yet with the request_irq().

Is there known way for dealing with such scenario?

You need to fix your irq handling code for your platform, this isn't a
UART issue at all.

good luck,

greg k-h