write_ID: timeout trying to write to VIPER (on QDSS displays)

[Ian! D. Allen [CGL]]

Using MIT's R4 xdvi on our MIT Xqdss colour VAXes often hangs the display.
Killing the X server gets things going again.   Echoing "xxx" to
/dev/console also unsticks things, but the system enters a
semi-comatose state.  A bunch of these appear in the uerf log:

EVENT CLASS                             OPERATIONAL EVENT
OS EVENT TYPE                  250.     ASCII MSG
SEQUENCE NUMBER                573.
OPERATING SYSTEM                        ULTRIX 32
OCCURRED/LOGGED ON                      Sun Nov 25 15:16:20 1990 EST
OCCURRED ON SYSTEM                      watdaffy
SYSTEM ID                 x08000000
SYSTYPE REG.              x01010000
                                        FIRMWARE REV = 1.
PROCESSOR TYPE                          KA630
MESSAGE
                                        write_ID: timeout trying to write to
                                         _VIPER

and the kernel becomes very sluggish:

    cgl# ping -v watdaffy
    64 bytes from 129.97.128.71: icmp_seq=0. time=10. ms
    64 bytes from 129.97.128.71: icmp_seq=6. time=0. ms
    64 bytes from 129.97.128.71: icmp_seq=1. time=5349. ms
    64 bytes from 129.97.128.71: icmp_seq=2. time=4349. ms
    64 bytes from 129.97.128.71: icmp_seq=3. time=3359. ms
    64 bytes from 129.97.128.71: icmp_seq=4. time=2359. ms
    64 bytes from 129.97.128.71: icmp_seq=5. time=1360. ms
    64 bytes from 129.97.128.71: icmp_seq=10. time=0. ms
    64 bytes from 129.97.128.71: icmp_seq=11. time=0. ms
    64 bytes from 129.97.128.71: icmp_seq=7. time=4879. ms
    64 bytes from 129.97.128.71: icmp_seq=8. time=3889. ms
    64 bytes from 129.97.128.71: icmp_seq=9. time=2890. ms
    64 bytes from 129.97.128.71: icmp_seq=16. time=0. ms
    64 bytes from 129.97.128.71: icmp_seq=17. time=0. ms
    64 bytes from 129.97.128.71: icmp_seq=12. time=5829. ms
    64 bytes from 129.97.128.71: icmp_seq=13. time=4839. ms
    64 bytes from 129.97.128.71: icmp_seq=14. time=3839. ms
    64 bytes from 129.97.128.71: icmp_seq=15. time=2849. ms
    64 bytes from 129.97.128.71: icmp_seq=20. time=0. ms

What is going on, and how can I fix it?  The only way out of this
seems to be a reboot.
-- 
-IAN! (Ian! D. Allen) idallen at watcgl.uwaterloo.ca idallen at watcgl.waterloo.edu
 [129.97.128.64]  Computer Graphics Lab/University of Waterloo/Ontario/Canada