FreeBSD-6 amr and ahd trouble

[Joerg Pulz]

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Hi guys,

I'm running an Fujitsu-Siemens Primergy RX300 dual-XEON hyperthreading 
enabled server with an onboard LSI MegaRAID controller and an Adaptec 
39320A Ultra320 dual channel SCSI adapter. The LSI MegaRAID controller is 
configured to RAID1 with two disk and one hotspare. On this array FreeBSD 
is installed.
Up to now, the system was running fine with FreeBSD-5.3 first and 
FreeBSD-5.4 now.
I tried to upgrade this beast to FreeBSD-6.0-RELEASE without success. The 
kernel is booting and detects all devices correctly but when it comes to 
read from the amr(4) the last thing i see is "GEOM: new disk amrd0" after 
that the system "hangs" and its nearly impossible to scroll the kernel 
messages up or down (Scroll lock pressed). then after a while there are a 
lot of SCSI error messages about SCB timeouts coming from the ahd(4).
I decided to boot the old RELENG_5_4 kernel and cvsup'ed the sources to 
RELENG_6 but i got the same results. booting from a FreeBSD-6.0-RELEASE 
bootonly CDRom got again the same results.
I searched google about this, and found something about a tuneable 
sysctl/loader setting called hw.pci.do_powerstate and tried it, but the 
same result. later i saw, that in RELENG_6 this tuneable is renamed and 
set to 0 anyway.
the next step was removing the Adaptec card to make sure this one is not 
interrupting the amr(4) but the only thing that happened was the SCSI 
error messages going away so this was not the problem.
I decided to give CURRENT from today a try, and it was working without 
any problems. I have tested CURRENT some steps back until i hit 700003 
dated to "Sun Sep 18 05:12:39 2005 UTC" which is exactly the same time the 
RELENG_6 branch was marked for 6.0-BETA5 and CURRENT was working with 
every point i checked out from cvs. Unfortunately 6.0-BETA5 is NOT 
working.
I checked out the sources for 6.0-BETA4 and it is working again. So 
somewhere between 6.0-BETA4 and 6.0-BETA5 the whole thing is broken, at 
least for me and my hardware.
I've seen some differences in sys/cam/cam_xpt.c, maybe these cause the 
trouble i have, but I'm not so deep in the FreeBSD kernel code to make 
this sure.

It would be nice if someone can take a look at this to get this fixed in 
RELENG_6.
Any patches to test are welcome.

regards
Joerg

- -- 
The beginning is the most important part of the work.
 				-Plato
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