Using joystick blocks network traffic
 

Hi,

It seems like my joystick and network conflict somehow!

When I play a game with a joystick, I can see the network traffic stops almost instantly in kppp statistics. When I close the game (assuming I didn't wait too long), the network traffic will start up again.

If I run the same games without the joystick disabled, the network traffic is fine. Even if my CPU usage is 99.9%, the network is fine.

I have Athlon AMD 3400+, using slamd64-10.1. My joystick is on /dev/input/js0 and is a Gravis Gamepad Pro connected to a game port provided by a SB Live! Value PCI sound card. I access the network by using ppp-on or kppp through a US Robotics 56K External FAX serial modem.

The games showing this problem include Snes9x and fceu (NES emulator).

I though it was a problem with CPU load at first, so I looked at /etc/ppp/options (tried turning off all kinds of compression), /etc/ppp/pppscript (modem init string), setserial, kernel options. Nothing helped.

Check the irqs and dma channels assigned to both your
modem and the USB hub. If they're the same, try changing
one of them in the BIOS.


Cheers,
Tink

Could the problem be USB related? The devices (modem, joystick) aren't using USB. My modem is connected with a serial cable, and the gamepad is connected to the PCI sound card.

The gameport/joystick is listed as this PCI device below . I tried setting latency with setpci to small values (8, then 2, then 0) thinking it would help stop hogging the system, but didn't make a difference.

Bus 0, device 7, function 1:
Class 0980: PCI device 1102:7002 (rev 8).
Master Capable. Latency=32.
I/O at 0xec00 [0xec07].

For some reason the gameport is never listed in /proc/interrupts, even when in use:
Perhaps it uses IRQ 185 like the soundcard it's connected to.

$ cat /proc/interrupts
CPU0
0: 888299 IO-APIC-edge timer
1: 3859 IO-APIC-edge i8042
4: 43980 IO-APIC-edge serial
8: 0 IO-APIC-edge rtc
9: 1 IO-APIC-level acpi
12: 43263 IO-APIC-edge i8042
14: 12587 IO-APIC-edge ide0
15: 4692 IO-APIC-edge ide1
177: 0 IO-APIC-level uhci_hcd, uhci_hcd, uhci_hcd, uhci_hcd, ehci_hcd
185: 8033 IO-APIC-level EMU10K1
193: 53739 IO-APIC-level nvidia
NMI: 131
LOC: 888118
ERR: 0
MIS: 0

$ cat /proc/pci
PCI devices found:
Bus 0, device 0, function 0:
Class 0600: PCI device 1106:3188 (rev 1).
Master Capable. Latency=8.
Prefetchable 32 bit memory at 0xd0000000 [0xdfffffff].
Bus 0, device 1, function 0:
Class 0604: PCI device 1106:b188 (rev 0).
Master Capable. No bursts. Min Gnt=14.
Bus 0, device 7, function 0:
Class 0401: PCI device 1102:0002 (rev 8).
IRQ 185.
Master Capable. Latency=32. Min Gnt=2.Max Lat=20.
I/O at 0xe800 [0xe81f].
Bus 0, device 7, function 1:
Class 0980: PCI device 1102:7002 (rev 8).
Master Capable. Latency=32.
I/O at 0xec00 [0xec07].
Bus 0, device 15, function 0:
Class 0101: PCI device 1106:0571 (rev 6).
IRQ 169.
Master Capable. Latency=32.
I/O at 0xfc00 [0xfc0f].
Bus 0, device 16, function 0:
Class 0c03: PCI device 1106:3038 (rev 129).
IRQ 177.
Master Capable. Latency=32.
I/O at 0xd800 [0xd81f].
Bus 0, device 16, function 1:
Class 0c03: PCI device 1106:3038 (rev 129).
IRQ 177.
Master Capable. Latency=32.
I/O at 0xdc00 [0xdc1f].
Bus 0, device 16, function 2:
Class 0c03: PCI device 1106:3038 (rev 129).
IRQ 177.
Master Capable. Latency=32.
I/O at 0xe000 [0xe01f].
Bus 0, device 16, function 3:
Class 0c03: PCI device 1106:3038 (rev 129).
IRQ 177.
Master Capable. Latency=32.
I/O at 0xe400 [0xe41f].
Bus 0, device 16, function 4:
Class 0c03: PCI device 1106:3104 (rev 134).
IRQ 177.
Master Capable. Latency=32.
Non-prefetchable 32 bit memory at 0xcffffe00 [0xcffffeff].
Bus 0, device 17, function 0:
Class 0601: PCI device 1106:3227 (rev 0).
Bus 0, device 24, function 0:
Class 0600: PCI device 1022:1100 (rev 0).
Bus 0, device 24, function 1:
Class 0600: PCI device 1022:1101 (rev 0).
Bus 0, device 24, function 2:
Class 0600: PCI device 1022:1102 (rev 0).
Bus 0, device 24, function 3:
Class 0600: PCI device 1022:1103 (rev 0).
Bus 1, device 0, function 0:
Class 0300: PCI device 10de:0330 (rev 161).
IRQ 193.
Master Capable. Latency=248. Min Gnt=5.Max Lat=1.
Non-prefetchable 32 bit memory at 0xce000000 [0xceffffff].
Prefetchable 32 bit memory at 0xb0000000 [0xbfffffff].

I rebuilt my kernel with preempt options and experimental PNP ACPI support turned off. No change :(

Also, I noticed that just doing "cat /dev/input/js0" is enough to halt all network traffic...

I think the serial port isn't being drained while the joystick is open.