[Serial 2.5]: packet drop problem (FE ?)

[Jean Tourrilhes <jt@bougret.hpl.hp.com>]

	Hi,

	I've got two identical boxes (dual P6 200MHz) talking to each
other through serial IrDA dongles (each attached to the first serial
port).

	One side has 2.4.20-pre8 :
-------------------------------
# cat /proc/tty/driver/serial 
serinfo:1.0 driver:5.05c revision:2001-07-08
0: uart:16550A port:3F8 irq:4 baud:9600 tx:5249946 rx:120379 RTS|DTR
1: uart:16550A port:2F8 irq:3 tx:0 rx:0 
-------------------------------

	The other side has 2.5.46 :
----------------------------
# cat /proc/tty/driver/serial 
serinfo:1.0 driver revision:
0: uart:16550A port:000003F8 irq:4 tx:19541287 rx:14370938 fe:1384 RTS|DTR
1: uart:16550A port:000002F8 irq:3 tx:39761 rx:3 RTS|DTR
[...]
# setserial -a /dev/ttyS0
/dev/ttyS0, Line 0, UART: 16550A, Port: 0x03f8, IRQ: 4
        Baud_base: 115200, close_delay: 500, divisor: 0
        closing_wait: 30000
        Flags: spd_normal skip_test
----------------------------

	Problem : a noticeable number of large packet from 2.4.X to
2.5.X are dropped (and retransmitted), whereas almost no packet from
2.5.X to 2.4.X are dropped.
	I tried swapping the IrDA dongles themselves, and this didn't
make any difference. No other device/driver is using irq4. I also try
using a FIR as a sender, and I still see this packet dropped in Rx in
2.5.X. And this used to work properly way back when I had 2.4.X on
this box.
	I'm kind of suspicious about the "fe" number above. Could
anybody tell me a bit more about what "fe" means ?

	Thanks...

	Jean