Re: Regression in 32-bit ppc kernel

Benjamin Herrenschmidt
2012-04-28T22:41:27Z

On Sat, 2012-04-28 at 13:09 -0500, Larry Finger wrote:
> I have done a little more debugging. The problem is definitely coming
> from
> drivers/tty/serial/pmac_zilog.c. I am getting ChanB interrupts while
> open, which
> causes the following code segment to return IRQ_NONE:
>
> if (r3 & (CHBEXT | CHBTxIP | CHBRxIP)) {
> if (!ZS_IS_OPEN(uap_a)) {
> pmz_debug("ChanB interrupt while open !\n");
> goto skip_b;
> }
> write_zsreg(uap_b, R0, RES_H_IUS);
> zssync(uap_b);
> if (r3 & CHBEXT)
>
> When this section is entered, r3 == 0x2 (CHBTxIP).
>
>
Ok. The debug code was meant to spell "while not open" btw :-)

I have some ideas what's going on. I think the irda stuff can trigger
interrupts during the open/close sequence before ZS_IS_OPEN is true.

I'll send a fix.

Cheers,
Ben.