YAM kernel driver IRQ question
Robert E Brose II
bob at kunk.jriver.com
Thu Apr 11 13:14:45 EST 2002
I'm trying to make the YAM kernel driver work with a 16550 PCI
board. I've got kernel 2.4.19-pre4-ben0. Haven't had any luck
with replies from the author so I thought I'd ask here.
The YAM is a HAM device. It works fine in intel linux AND on
an PPC rs6k PREP linux box so it doesn't appear to have endian
The YAM uses the serial hardware DIRECTLY without using the
kernel serial driver. It uses some of the hardware status
lines for purposes other than what a normal serial port does.
On the PREP machine, the serial ports are just like a PC, COM1 on
3F8 irq 4 and COM2 on 2F8 irq 3.
On my 7500 the board shows up on 0x890 and 0x880 on IRQ 24.
The YAM driver handles the port ok but chokes on the IRQ. In the
code it was checking the specified IRQ against a maximum of 15
(PeeCee mindset). I changed it to 31 and the driver tries to
run but I get an error that appears to indicate the interrupts are
I know the board is working OK because I can use setserial on port
0x890 and irq 24, throw a modem on it and all is well..
What I'm wondering is if anyone who knows about the enabling,
etc of IRQS on pmacs can tell me if there anything I might have
to look out for when enabling interrupt 24 as against interrupt 3
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