Hello,
Sagar Borikar wrote:
I am currently working on NAS which has sil 3114 SATA controller.There
is some strange scenario reported by product validation team.When I
insert the drive and remove immediately without settling down,
the system gets reset after roughly 30 seconds. Tried to capture the
log from drivers but couldn't get any of the stack dump or kernel
panic in due course. I am using 2.6.18 kernel and sata_sil is enabled.
Rest functionality works pretty fine. But only when I do insert and
remove without time gap, the system resets. Strange thing is when I
insert the disk and remove it back immediately the interrupt line
asserted is only for insert and not for removal. But if I insert
another disk, then this interrupt is recognised properly. Sata
controller is not getting interrupt for second immediate drive
removal.Now based on the logs captured, I can say that in this typical
case, sata controller first gets the request to handle drive
insertion. It waits for some time to check the status to ensure that
it is proper request and after that it again reads the line. It finds
that drive is removed till that time. But actually SATA controller is
not detecting the remove instance as it is not reflected in GPIO
transition as well. So I get messages like COMRESET Failed and hard
reset failed. This doesn't happen if I insert back the drive
immediately. The system immediately recovers.
Okay, that was one long paragraph. :-)
The behavior itself (sans triggering machine reset) is intended. libata
EH doesn't rely on the edge events (PHY status changed). It relies on
level state (PHY readiness) and as long as at least one PHY event is
triggered after link status has changed, it doesn't care what polarity
those events are or how many of them are. That was the design decision
made for robustness.
ata2: exception Emask 0x10 SAct 0x0 SErr 0x50000 action 0x2 frozen
ata2: hard resetting port
ata2: port is slow to respond, please be patient
ata2: port failed to respond (30 secs) ---------------------> At this
state, actually the drive is removed. But not detected.
ata2: COMRESET failed (device not ready)
ata2: hardreset failed, retrying in 5 secs
ata2: hard resetting port
ata2: SATA link down (SStatus 0 SControl 310)
ata2: EH complete
This is a quite old kernel, right? Recent ones take much shorter to
detect the condition.
PMON2000 MIPS Initializing. Standby...
ERRORPC=bfc00004 CONFIG=0042e4bb STATUS=00400000
CPU PRID 000034c1, MaskID 00001320
Initializing caches...done (CONFIG=0042e4bb)
Switching to runtime address map...done
Setting up SDRAM controller: sdram config 0x80010000
master clock 100 Mhz, MulFundBIU 0x02, DivXSDRAM 0x02
sdram freq 0x09ef21aa hz, sdram period: 0x06 nsec
dimm0: density 256Mbit, width 16, single-sided, unbuffered, size
0x08000000
supported CAS latency: 2.5 2, using 2.5 cycles, byte18=0x0c
RAS to CAS delay (tRCD) 0x12 nsec, byte29=0x
Okay, and the machine got reboot. It's weird that the reset happens
*after* EH is complete. After EH complete is printed, libata won't
touch the hardware. I'm sorry but I don't have any clue why the machine
is getting rebooted. Does the machine reset on oops?
--
tejun
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