HELP: Strange "Xlib: sequence lost" problem with remote client.

HELP: Strange "Xlib: sequence lost" problem with remote client.

Post by John G Log » Fri, 07 Feb 1997 04:00:00



I've been having a bit of a problem getting certain clients to function
properly when I run them from a remote SunOS system to my Linux box.  The
typical mode of failure is for the client to freeze in the middle of a
redraw, and a passel of "sequence lost" error messages are written to
stderr on the client side.  I then have to kill -9 the client as it's
nonresponsive to anything else.

I've seen this behavior with Netscape 3.0, Viewtrace 5.3 (Viewlogic), and
a few other programs.  I have only seen this problem when I'm running the
server on Linux through my ethernet, over an Ascend ethernet to ISDN
router, to the remote network.  Both XFree86 and Metro X exhibit the
behavior.

I'm trying to isolate the problem with little results.  I know these
clients work fine to X11R6 or OpenWindows over local ethernet, ISDN, and
v34 PPP.  I've tried the clients over ISDN to the offending local machine
running Win95 and the eXodus demo, and that seems to work.  Ditto for my
Mac running eXodus.

When I run Linux/Metro X using PPP instead of Ethernet/ISDN, I don't seem
to have problems, other than that it's *y slow.

On the client side, I've tried SunOS 4.1.3 and Solaris versions of the
Viewtrace client to see if there was a problem with Xlib on that side.
Both failed after a short period of time.

I started looking at the tcpdump to try to see what was going on, and I
saw that I was getting fragmented datagrams every time the client would
crash.  It appears the correlation is pretty strong, but I don't know much
about TCP/IP so it doesn't tell me what the problem is.

Anyone have a clue as to what's going on?  It's driving me crazy, and I'd
sure hate to have to go to Windows to run my X apps.  It doesn't seem
natural, and I don't want to buy any more X servers.  I'd really
appreciate the help.

Lastly, all the relevant info I could scrounge up:

=======================================================================

Configuration:

Intel P5/166 CPU, Triton chipset, Matrox Millenium, 3Com EtherLink XL
Ascend P75 (v4.6C s/w).

I've tried Linux 2.0.18 (Red Hat 4.0) and 2.0.27 (Red Hat 4.1), along with
2 versions of the 3c59x.c driver, as well as the beta 3c900.c driver.

I've tried XFree86 3.2 and Metro-X 3.1.2.

=======================================================================

Here's a look at the error from Viewtrace (a waveform viewer):

Xlib:  sequence lost (0x10026 > 0xe0b) in reply type 0x3!
Xlib:  sequence lost (0x10002 > 0xe0b) in reply type 0x0!
BadRequest error received from X Display Server.
251 error received from X Display Server.
Xlib:  sequence lost (0x10015 > 0xe0b) in reply type 0x0!
248 error received from X Display Server.
248 error received from X Display Server.
248 error received from X Display Server.
BadValue error received from X Display Server.
Xlib:  sequence lost (0x10002 > 0xe0b) in reply type 0x0!
0 error received from X Display Server.
251 error received from X Display Server.
Xlib:  sequence lost (0x10000 > 0xe0b) in reply type 0x0!
0 error received from X Display Server.

=======================================================================

And here's what Netscape spat out:

netscape: X Error of failed request:  BadDrawable (invalid Pixmap or
Window parameter)
  Major opcode of failed request:  0 ()
  Resource id in failed request:  0x20002
  Serial number of failed request:  3
  Current serial number in output stream:  38827

netscape: X Error of failed request:  BadValue (integer parameter out of
range for operation)
  Major opcode of failed request:  0 ()
  Value in failed request:  0x10001
  Serial number of failed request:  7
  Current serial number in output stream:  38827

netscape: X Error of failed request:  BadValue (integer parameter out of
range for operation)
  Major opcode of failed request:  0 ()
  Value in failed request:  0x9000a
  Serial number of failed request:  9
  Current serial number in output stream:  38827

[and so on...]

=======================================================================

And here's a section of the tcpdump:

11:46:19.529389 vitsemi.2077 > dnai-207-33-149-122.6000: P
373005:373049(44) ack 35525 win 4096
11:46:19.549389 dnai-207-33-149-122.6000 > vitsemi.2077: . ack 373049 win 31744
11:46:19.729389 dnai-207-33-149-122.6000 > vitsemi.2077: P



11:46:19.939389 vitsemi.2077 > dnai-207-33-149-122.6000: . ack 39621 win 2048
11:46:20.139389 dnai-207-33-149-122.6000 > vitsemi.2077: P


11:46:20.169389 vitsemi.2077 > dnai-207-33-149-122.6000: P
373049:373057(8) ack 39621 win 2048
11:46:20.169389 vitsemi.2077 > dnai-207-33-149-122.6000: . ack 39621 win 3488
11:46:20.189389 dnai-207-33-149-122.6000 > vitsemi.2077: . ack 373057 win 31744
11:46:20.289389 vitsemi.2077 > dnai-207-33-149-122.6000: . ack 39621 win 4096
11:46:20.489389 dnai-207-33-149-122.6000 > vitsemi.2077: P


11:46:20.639389 vitsemi.2077 > dnai-207-33-149-122.6000: . ack 39621 win 4096

--
jgl


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