Serial issue

From: Lee Revell
Date: Thu Aug 17 2006 - 20:44:48 EST

I've found a weird serial bug. My host is a Via EPIA M-6000 running
2.6.17 connected to a PPC Yosemite board running 2.6.13.

In all cases the serial console works great. But, with the default
setting of IRQ 4, Kermit file transfers via the serial interface simply
time out. However if I use polling mode (setserial /dev/ttyS0 irq 0 on
the host), file transfers work.

When set to IRQ 4, the interrupt count does increase.

# cat /proc/tty/driver/serial
serinfo:1.0 driver revision:
0: uart:16550A port:000003F8 irq:4 tx:267 rx:667 DSR|CD
1: uart:16550A port:000002F8 irq:3 tx:0 rx:0
2: uart:unknown port:000003E8 irq:4
3: uart:unknown port:000002E8 irq:3

# setserial /dev/ttyS0
/dev/ttyS0, UART: 16550A, Port: 0x03f8, IRQ: 4

# cat /proc/interrupts
0: 175715279 XT-PIC timer
1: 137763 XT-PIC i8042
2: 0 XT-PIC cascade
4: 326 XT-PIC serial

Any ideas? I'm guessing it might be a quirk of the VIA chipset?


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