[PATCH][RFC] usbatm.[ch]: cleanup and OAM F5 loopback

[matthieu castet]

Hi Roman,

Roman Kagan wrote:
> On Sun, Mar 13, 2005 at 11:21:35PM +0100, matthieu castet wrote:
> 
>>I wasn't able to reproduce crc errors, but I have "bogus pdu_length" and
>>all the status are correct.
>>"bogus pdu_length" indicate it miss data in the atm trame ?
> 
> 
> Then the modem doesn't seem to be guilty.  The message means that your
> ISP sends data in bigger units than was requested by the ATM layer or
> userspace (e.g. pppd), and from your log I gather that the difference
> is no greater than 48 bytes (usbatm aligns the PDU to ATM payload).
There are all greater that 48 bytes [1].
And because ATM_CELL_PAYLOAD is 48, it seem there are missing atm cells.

> 
> I guess you need to check MRU setting in pppd (or similar stuff in
> whatever higher level protocol you are using).
I use IP over atm.
I change the mtu with ifconfig and it does nothing.

regards,

Matthieu

[1]
$sudo grep "bogus pdu_length" /var/log/syslog | awk '{printf "%d %d %d 
%d\n", $10 - $12,($10 - $12)/48, $10, $12}' | sort -n | uniq
48 1 1008 960
48 1 1440 1392
48 1 1536 1488
96 2 1008 912
96 2 1440 1344
96 2 1536 1440
144 3 1008 864
144 3 1440 1296
144 3 1536 1392
192 4 1440 1248
192 4 1536 1344
240 5 1440 1200
240 5 1536 1296
288 6 1440 1152
288 6 1536 1248
336 7 1440 1104
336 7 1536 1200