To see if it helps avoid the infrequent situations where PC104 interrupts cease to be serviced, I changed the second emerald board on the low DSM to use IRQ4:
ddn set_emerald -e /dev/emerald1 0x140 4 /etc/init.d/emerald start dup
After that, here's the current configuration. Since the config is saved in the EEPROM on the emerald, it should come up in this state after a reboot:
root@low root# set_emerald /dev/emerald0 current port config: port 0x100 irq 3 port 0x108 irq 3 port 0x110 irq 3 port 0x118 irq 3 port 0x120 irq 3 port 0x128 irq 3 port 0x130 irq 3 port 0x138 irq 3 root@low root# set_emerald /dev/emerald1 current port config: port 0x140 irq 4 port 0x148 irq 4 port 0x150 irq 4 port 0x158 irq 4 port 0x160 irq 4 port 0x168 irq 4 port 0x170 irq 4 port 0x178 irq 4 root@low root# cat /proc/tty/driver/serial serinfo:1.0 driver revision: 0: uart:XScale mmio:0x40100000 irq:38 tx:3573 rx:0 RTS|DTR 1: uart:XScale mmio:0x40200000 irq:37 tx:20 rx:22438852 RTS|CTS|DTR 2: uart:XScale mmio:0x40700000 irq:36 tx:0 rx:2926614 RTS|DTR 3: uart:16550A mmio:0x14300010 irq:116 tx:5235 rx:11378936 fe:19 RTS|DTR 4: uart:16550A mmio:0x14300000 irq:115 tx:27 rx:20225583 RTS|CTS|DTR 5: uart:ST16654 port:F1000100 irq:3 tx:0 rx:0 6: uart:ST16654 port:F1000108 irq:3 tx:0 rx:0 7: uart:ST16654 port:F1000110 irq:3 tx:0 rx:80133446 fe:11 RTS|CTS|DTR 8: uart:ST16654 port:F1000118 irq:3 tx:0 rx:411388 RTS|CTS|DTR 9: uart:ST16654 port:F1000120 irq:3 tx:15 rx:22437904 RTS|CTS|DTR 10: uart:ST16654 port:F1000128 irq:3 tx:0 rx:2947936 RTS|DTR 11: uart:ST16654 port:F1000130 irq:3 tx:0 rx:427094 RTS|CTS|DTR 12: uart:ST16654 port:F1000138 irq:3 tx:15 rx:19230482 fe:1 RTS|CTS|DTR 13: uart:ST16654 port:F1000140 irq:4 tx:0 rx:2945680 RTS|DTR 14: uart:ST16654 port:F1000148 irq:4 tx:0 rx:80119263 fe:17 RTS|CTS|DTR 15: uart:ST16654 port:F1000150 irq:4 tx:0 rx:410093 RTS|DTR 16: uart:ST16654 port:F1000158 irq:4 tx:27 rx:20204969 fe:11 RTS|CTS|DTR|DSR|CD|RI 17: uart:ST16654 port:F1000160 irq:4 tx:0 rx:0 18: uart:ST16654 port:F1000168 irq:4 tx:0 rx:2917645 RTS|DTR 19: uart:ST16654 port:F1000170 irq:4 tx:15 rx:19234163 fe:1 RTS|CTS|DTR 20: uart:ST16654 port:F1000178 irq:4 tx:0 rx:2491823 RTS|CTS|DTR root@low root# irqs Counting interrupts over 5 seconds ... IRQ Interrupt Type Total Int Int/sec ------------------------------------------------------ 3: ISA serial: 742 148.4 4: ISA serial: 819 163.8 24: GPIO-l eth0: 58 11.6 25: GPIO-l GPIO1-PC104: 1412 282.4 36: SC serial: 15 3 37: SC serial: 102 20.4 42: SC ost0: 509 101.8 114: GPIO isp116x-hcd:usb1: 92 18.4 115: GPIO serial: 227 45.4 116: GPIO serial: 100 20 120: GPIO pata_pcmcia: 8 1.6