RE: Hangs after "Loading" but before "Uncompressing"

From: Markley, Todd (Todd.Markley@qwest.com)
Date: Wed Jan 26 2000 - 13:58:12 EST


Dick:
        I think you are asking me to comment out the `je a20_wait`
line in setup.S. I have now tried this and get the same results.
The problem system still hangs just before "Uncompressing" and
the same kernel boots fine on my laptop.

      At this stage of the boot is it possible to insert some
kind of PRINT debugging in setup.S to find out where it hangs?
Something like:

               dbgmsg:
                          .ascii "DBGA20"

                    -------------------
               dbgpnt:
                           push cx
                           push bx
                           push bp
                           push ax
                           mov cx,#9
                           mov bx,#0x0007
                           mov bp,#dbgmsg
                           mov ax,#0x1301
                           int 0x10
                           pop ax
                           pop bp
                           pop bx
                           pop cx
                           ret
                    -------------------
                a20_wait:
                           call dbgpnt

      I am not clear on the state of the hardware at this point
and I am not clear what the "mov bx,#0x0007" is doing, or if it
is safe at this stage. So forgive me if I have suggested something
foolish here. I have very little experience with programming at
this level. If I can get something to print out then I can try
to find where the system hangs.

      And I would still like to know what is different about the
RedHat install kernel that boots just fine.

Todd

-----Original Message-----
From: Richard B. Johnson [mailto:root@chaos.analogic.com]
Sent: Wednesday, January 26, 2000 8:55 AM
To: 'linux-kernel@vger.rutgers.edu '
Subject: RE: Hangs after "Loading" but before "Uncompressing"

There isn't anything in setup.S that would run differently on a
'386 to a '686. The CPU-dependent stuff runs after everything is
uncompressed. That said, there is a loop in setup.S that I don't
like. At line 690, the label, a20_wait, 4 lines later a `je a20_wait`.

Comment that out with a '#' and see if it boots. This alias may remain
in the cache forever so it's not a good way to see if a20 is enabled.

Let me know if it 'fixes' the problem. If so, the person who rewrote
setup.S should find another way to check on a20.

Cheers,
Dick Johnson

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