SPARC64: input/output error on softraid 5 with more than 8 disks

I'm forwarding this to a few other lists just to see if i can get some 
more input on it. I would like to think this is an arch specific bug as 
i imagine there are people using raid 5 with more than 8 disks on amd64 
/ i386. However i haven't tried this on amd64, so i am not certain.

1. Steps to reproduce (can be done in bsd.rd after issuing MAKEDEV for 
all disks)

Using sd2-sd11 for this example.

disklabel -E sd2(sd3,sd4,etc..) - Create partition "a" with all disk 
space as RAID type all disks are the same model.
bioctl -c 5 -l sd2a,sd3a,etc... softraid0 - comes out as sd12
disklabel -E sd12 - Create partition "a" with all disk space as BSD type
newfs sd12a
mount /dev/sd12a /mnt
cd /mnt
dd if=/dev/zero of=test bs=1m count=128

2. Output Received

dd will fail immediately with "Input/Output Error" with 0 records 
written. dmesg shows no errors. The test file is visible on the 
filesystem however.

3. Dmesg output, will post tomorrow. As stated below, this happens on 
two different sparc64 hosts with completely different hardware, disks, 
HBA's, and disk shelves. There are no dmesg errors added when dd fails.

4. Third party software, can be done in a base install or in bsd.rd. No 
third party software needed.

5. No kernel panic, system keep chugging along, filesystem stays 
mounted, fsck comes back clean, upon reboot raid is still in good 
standing and filesystem checks still pass.

-------- Original Message --------
Subject: Input/Output error on softraid 5 with more that 8 disks
Date: 2016-10-05 19:19
 From: [email protected]
To: [email protected]

Tested on a Sun E6K and Sun V210. It seems that if i create a raid 5 
array bigger than 8 disks (U320 SCSI) using softraid, i get a rather 
vague "Input / Output" error why attempting to write any significantly 
large data (dd if=/dev/zero of=/mnt/blah bs=1m count=128). newfs creates 
the filesystem fine and fsck comes back clean but trying to put anything 
on the array doesn't seem to do anything.

I was just wondering if this is something that has been reported in the 
past or if I'm the first to uncover it? I have obtained the same results 
from various hardware which seems to point to the softraid driver.

Hardware Tested

HBA's

qlw: isp1000, isp1040, isp10160
esp: fas336

Disk Shelfs

StorEdge D1000
StorEdge 3320