Re: AHCI/ADA regression?

On Mon, 23 May 2016 13:51:05 -0400
"Kenneth D. Merry" <ken_at_FreeBSD.ORG> wrote:

> On Sat, May 21, 2016 at 10:09:49 +0200, Gary Jennejohn wrote:
> > There appears to be a regression in AHCI/ADA behavior since r300207.
> > 
> > Starting a test kernel at r300293 results in extremely long timeouts
> > probing ahcich2 for non-existent multiplier ports.
> > 
> > Here some kernel output:  
> 
> Is this dmesg output with or without the problem?
> 

Actually it's the same with and without the problem.  The only real
difference is the timeouts.

> > ahci0: <AMD SB7x0/SB8x0/SB9x0 AHCI SATA controller>
> > port 0xff00-0xff07,0xfe00-0xfe03,0xfd00-0xfd07,0xfc00-0xfc03,
> > 0xfb00-0xfb0f mem 0xfe02f000-0xfe02f3ff irq 22 at device 17.0 on pci0
> > 
> > ahci0: AHCI v1.10 with 6 3Gbps ports, Port Multiplier supported  
> 
> Has the controller always claimed support for Port Multipliers?
> 

Yes, this from today's dmesg.boot:
ahci0: AHCI v1.10 with 6 3Gbps ports, Port Multiplier supported

> > ahcich2: <AHCI channel> at channel 2 on ahci0
> > 
> > ada1 at ahcich2 bus 0 scbus2 target 0 lun 0
> > 
> > /dev/ada1p1 on /home (ufs, local, journaled soft-updates)
> > 
> > An older kernel at r299170 does not exhibit this peculiar behavior and
> > mounts /home with no delays.  
> 
> Are you able to send dmesg output before and after?
> 

Before is easy, since I have a dmesg.boot.  After - I'll have to
copy it from the screen since I don't have the patience to wait
for booting to complete.  The above is pretty much after, but I
can copy down the timeout messages which arise when the
mulitplier ports are probed (no disk is present on any of them,
so it takes forever).

The question in my mind is - why are "empty" multiplier ports being
probed with the new code but not with the old code?

-- 
Gary Jennejohn