Linux for SGI Visual Workstations
Linux 2.2.10 + Red Hat 6.0

KNOWN PROBLEMS

Updated: July 19, 1999

Some of the known problems are minor annoyances, but others can hang the system.

Please read carefully to avoid frustration.

PCI Limitations

Enough of the PCI infrastructure (interrupts, etc) exists to permit use of the Intel 82557 Ethernet and Intel PIIX4/UHCI USB drivers as well as SOME PCI cards in the expansion slots.

The aic7xxx driver works fine with the Adaptec AHA-3950U2D card/chip.

The Qlogic 1080 chip/card driver works fine [July 8].

But, the sym53c8xx does NOT WORK with the Symbios Logic 53C895 chip on the Symbios Logic Sym8951U card.

Note: these are just some cards I had handy... no endorsement or critique of any product or vendor is implied.

Time base problems

There have been reports of time base variance, for example:

the duration of select() with a timeout of 2 seconds
varies with an error between -5000 to +5000 microseconds

Something more like +/- 500 is expected.

Also if the kernel is compiled with CONFIG_RTC=y then /sbin/hwclock will wait indefinitely when called from /etc/rc.d/rc.sysinit. One workaround is to NOT compile with CONFIG_RTC=y the other is to remove the /dev/rtc link. [This is related to the interrupts on the slave PIIX "8259" not being wired up at present]

Physical memory hardwired to 128 MB

It is possible to hardwire a different value, but 128 MB will always work so the current patch uses that.

MP interrupts not distributed

Even SMP kernels for Visual Workstation still direct all device interrupts to cpu0.

Not all USB mice work

The "native" Linux kernel USB code does not appear to support "wheel" mice (or any that speak only HID).

The USB kbd shipped with Visual Workstations presents only this HID protocol to the system from its PS/2 mouse port.

WORKAROUND: get a "basic" USB mouse and plug it directly into the system.

PC boot/recovery floppies will not work

The boot/recovery floppies that come with typical Linux distributions will NOT WORK on Visual Workstations. These floppies generally expect a BIOS-based computer -- the Visual Workstations use ARC boot firmware which provides _some_ BIOS emulation but not enough to run these boot/recovery floppies.

See elsewhere in these instructions for what to do instead on Visual Workstations.

Problem mounting root file system

On some machines in some situations the kernel panics because it cannot mount the root file system. You'll see this message:

VFS: Unable to mount root fs on 00:00

(Or, you'll see some garbage hex numbers instead of the '00:00' above.)

WORKAROUND: Create a new Boot Selection based on a Copy of the "Linux RX" Boot Selection. In this new COPY change OSLoadOptions to "root=/dev/hdXX" -- XX is your IDE disk root partition: a1, b2, etc.

Passwd problems

Here is a fixed libpwdb.so. If you have any trouble setting (or getting rid of) passwords using "passwd" or "passwd -d" then this dso might help. It's a replacement for /lib/libpwdb.so.0.58 on Red Hat 6.0. (Watch those symlinks in /lib!) This issue is not specific to Linux for Visual Workstations,

Here is some info and a src patch regarding this problem:

I installed redhat 6.0, including libpwdb 0.58, on a machine with
some passwordless accounts, and found out that I couldn't log in
anymore to those accounts.  After a little debugging, I figured out
why.  The patch is affixed below.

To reproduce the problem, I used the check_user program in
libpam-0.66/examples.  Create /etc/passwd with this line:

	fred::998:998:Fred:/home/fred:/bin/csh

Create the following /etc/pam.d/check:

	#%PAM-1.0
	auth	required	/lib/security/pam_pwdb.so shadow nullok
	account	required	/lib/security/pam_permit.so

and run "check_user fred".  Observe the ominous password prompt.
Observe the even more ominous, "Not Authenticated".

I'll leave it to you to determine whether I really fixed the problem,
but it started working (and, better, logins started working too).

diff -ru pwdb-0.58.orig/libpwdb/pwdb/interface/unix/user.c pwdb-0.58/libpwdb/pwdb/interface/unix/user.c
--- pwdb-0.58.orig/libpwdb/pwdb/interface/unix/user.c   Sat Apr 10 03:40:24 1999
+++ pwdb-0.58/libpwdb/pwdb/interface/unix/user.c        Mon May 10 11:04:59 1999
@@ -130,7 +130,7 @@
      * only set the passwd if it is not a single character -- indicating
      * that the passwd is to be found in another database
      */   
-    if (strlen(pwd->pw_passwd) > 1) {
+    if (strlen(pwd->pw_passwd) != 1) {
         retval = pwdb_set_entry(*p, "passwd", pwd->pw_passwd, 1+strlen(pwd->pw_passwd),
                                NULL, txtcpy, 1+strlen(pwd->pw_passwd));
         if (retval != PWDB_SUCCESS) {

Mouseconfig hangs system

/usr/sbin/mouseconfig hangs the system hard.

WORKAROUND #1: Do NOT compile the serial driver into the kernel.

WORKAROUND #2: Do not run mouseconfig.

mouseconfig knows nothing about USB mice so it won't do anything useful anyways.

See the X gunk in the post-install instructions for details on how to teach X about the USB mouse.

(These instructions do NOT include any details on configuring the USB mouse with gpm -- for using the mouse with the text virtual terminal).


arclx problem

On some systems arclx.exe fails to boot the kernel from Floppy #1. Some initial boot loading messages appear in a white-framed blue box the last one being something like "ARC opening..." and then the floppy light stays on forever.

A workaround is to use the (now old) larc.exe bootloader. Simply ADD larc.exe to Floppy #1 and change OSLoader in the "Linux RX" Boot Selection to read "larc.exe" (That first letter is a small L.)