Re: Regression in 32-bit ppc kernel

[Larry Finger]

On 04/27/2012 07:42 PM, Benjamin Herrenschmidt wrote:
> Ok, so you do have a serial port, probably two even :-) One of them is
> connected to the infra red transceiver and the other one is probably
> connected to the internal modem.
>
> (The modem itself might not use it, some of these machines use an
> i2s/i2c modem, some use a usb modem, but the serial port is wired to the
> connector regardless).

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).

Larry
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