Re: Linux 2.5.44-ac3

[Jason Williams <jason_williams@suth.com>]

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On Fri, 2002-10-25 at 06:19, Alan Cox wrote:
> ** I strongly recommend saying N to IDE TCQ options otherwise this
>    should hopefully build and run happily.
> 

Ok, so I did some "head-banging-against-the-wall" digging into the IDE
code(my wall is dented now...) and I found where hwif->mate gets
populated.  Checking out this code and the code of the calling function,
I found that since the Primary interface is disabled, the first call to
the ide_hwif_configure is for the secondary channel. Being the first
call to the function the mate argument to the ide_hwif_configure
function is null.    Since the mate argument is null this makes the
secondary interface have no mate, and it needs one(don't we all). I
figured it might be alright to populate it's hwif->mate var with a copy
of itself.  I thought about this and if that var gets called elsewhere
in the code, worst it would do is attempt to double initialize something
on that interface, I think.  So it seems like a few lines right by the
assignment of hwif->mate might take care of this.  I basically check
mate for null, AND port for not zero.  If those 2 conditions are met, I
set hwif->mate to a copy of hwif itself and let it go.  It looks like
this runs ok on  my boxen. I am just wondering everyone's opinion on
this proposed fix.


Jason Williams
 

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diff -u -r linux-2.5.44-ac3/drivers/ide/setup-pci.c linux-2.5.44-ac3-idefix/drivers/ide/setup-pci.c
--- linux-2.5.44-ac3/drivers/ide/setup-pci.c	2002-10-18 23:01:49.000000000 -0500
+++ linux-2.5.44-ac3-idefix/drivers/ide/setup-pci.c	2002-10-25 10:54:30.000000000 -0500
@@ -472,6 +472,16 @@
 		hwif->mate = mate;
 		mate->mate = hwif;
 	}
+        else if(port){
+               // if mate is NULL and port is 1
+               // then we have a secondary without a primary
+               // which can happen on some bioses
+               // to avoid a null exception later in the code
+               // we populate mate with itself.
+               // Worst case is it says the controller is already 
+               // initialized later.
+               hwif->mate = hwif;
+        }
 	return hwif;
 }