This an annoyance that I've seen since 2.0.3x that I decided to mention in
case in can or should be fixed.
SUMMARY: aha152x with DAT combined with IDE activity (i.e. tar) blocks
PPP. If I am accessing a SCSI-DAT drive (HP SureStore) via my aha152x
card AND writing data to IDE disk, the system loses the ability to process
serial port information.
Before the backup begins, ifconfig shows the following stats for ppp0:
ppp0 Link encap:Point-to-Point Protocol
inet addr:x.x.x.z P-t-P:x.x.x.y Mask:255.255.255.255
UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1500 Metric:1
RX packets:11463 errors:0 dropped:0 overruns:0 frame:0
TX packets:7863 errors:0 dropped:0 overruns:0 carrier:0
collisions:0
Now. Let's say I have a nice big tar on sitting on the tape. If I do:
bash# tar -tvf /dev/nst0 >/dev/null 2>&1 &
No problems. However, if I simply change this to:
bash# tar -tvf /dev/nst0 >tar.log 2>&1 &
Most packets get dropped. Note that tar.log is being created on an
old WD IDE hard drive. Pinging from the local machine causes the SD
modem light to blink, the RD light blinks (about 100 ms later :-) and no
ICMP reply shows up. About 2 in 10 get through. ifconfig now reports:
ppp0 Link encap:Point-to-Point Protocol
inet addr:x.x.x.z P-t-P:x.x.x.y Mask:255.255.255.255
UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1500 Metric:1
RX packets:12076 errors:83 dropped:0 overruns:0 frame:83
TX packets:8309 errors:0 dropped:0 overruns:0 carrier:0
collisions:0
(note that there was some activity between these two ifconfig reports that
occurred without the tape drive running, so I can't say exactly x out of y
packets were dropped). Trying to access the other end of the link
involves a 15-20 second latency for any data.
Bug or feature?
-- /==============================\ | David Mansfield | | david@cobite.com | | | | (212) 536-9115 | \==============================/
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/