Spurious completions during NCQ

Spurious completions during NCQ

[Hugo Mills]

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   I'm getting these on my Dell Latitude D830:

Feb 15 13:06:00 willow kernel: ata1.00: exception Emask 0x2 SAct 0x4 SErr 0x0 action 0x2 frozen
Feb 15 13:06:00 willow kernel: ata1.00: spurious completions during NCQ issue=0x0 SAct=0x4 FIS=004040a1:00000002
Feb 15 13:06:00 willow kernel: ata1.00: cmd 61/10:10:26:fb:c4/00:00:02:00:00/40 tag 2 cdb 0x0 data 8192 out
Feb 15 13:06:00 willow kernel:          res 40/00:10:26:fb:c4/00:00:02:00:00/40 Emask 0x2 (HSM violation)
Feb 15 13:06:00 willow kernel: ata1: soft resetting port
Feb 15 13:06:00 willow kernel: ata1: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
Feb 15 13:06:00 willow kernel: ata1.00: configured for UDMA/133
Feb 15 13:06:00 willow kernel: ata1: EH complete
Feb 15 13:06:00 willow kernel: sd 0:0:0:0: [sda] 312581808 512-byte hardware sectors (160042 MB)
Feb 15 13:06:00 willow kernel: sd 0:0:0:0: [sda] Write Protect is off
Feb 15 13:06:00 willow kernel: sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00
Feb 15 13:06:00 willow kernel: sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA

   In some cases, there are several cmd/res lines listed. It's
happening about once an hour or so (not correlated with any other
event that I can see). It doesn't seem to be affecting operation of
the machine, but it's making me nervous.

   Can anyone set my mind at rest? (Or suggest a fix?)

uname -a reports:
Linux willow 2.6.23.1-hrt3 #1 SMP Sun Nov 4 14:51:20 GMT 2007 x86_64 GNU/Linux

   It's a kernel.org kernel with the patch for tickless operation on
amd64.

hdparm -i reports:

/dev/sda:

 Model=ST9160823AS                             , FwRev=3.ADC   , SerialNo=            5NK0C448
 Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs RotSpdTol>.5% }
 RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=4
 BuffType=unknown, BuffSize=8192kB, MaxMultSect=16, MultSect=?8?
 CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=268435455
 IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
 PIO modes:  pio0 pio1 pio2 pio3 pio4 
 DMA modes:  mdma0 mdma1 mdma2 
 UDMA modes: udma0 udma1 udma2 udma3 udma4 udma5 
 AdvancedPM=yes: unknown setting WriteCache=enabled
 Drive conforms to: Unspecified:  ATA/ATAPI-1,2,3,4,5,6,7

 * signifies the current active mode


   Hugo.

-- 
=== Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk ===
  PGP key: 515C238D from wwwkeys.eu.pgp.net or http://www.carfax.org.uk
              --- w.w.w.  : England's batting scorecard ---              

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Re: Spurious completions during NCQ

[Calvin Walton]

On Fri, 2008-02-15 at 13:46 +0000, Hugo Mills wrote:
> I'm getting these on my Dell Latitude D830:
> 
> Feb 15 13:06:00 willow kernel: ata1.00: exception Emask 0x2 SAct 0x4 SErr 0x0 action 0x2 frozen
> Feb 15 13:06:00 willow kernel: ata1.00: spurious completions during NCQ issue=0x0 SAct=0x4 FIS=004040a1:00000002

>    In some cases, there are several cmd/res lines listed. It's
> happening about once an hour or so (not correlated with any other
> event that I can see). It doesn't seem to be affecting operation of
> the machine, but it's making me nervous.
> 
>    Can anyone set my mind at rest? (Or suggest a fix?)

You didn't mention which SATA chipset your laptop has, but some quick
googling says that it's AHCI. Until 2.6.24, the AHCI driver has a
problem where it'll report superious NCQ completions due to a bug in the
driver logic.

> uname -a reports:
> Linux willow 2.6.23.1-hrt3 #1 SMP Sun Nov 4 14:51:20 GMT 2007 x86_64 GNU/Linux

The fix is simple, upgrade your kernel to 2.6.24 :)

>    It's a kernel.org kernel with the patch for tickless operation on
> amd64.

Handily, the 2.6.24 kernel.org kernel includes amd64 tickless support
already.

-- 
Calvin Walton <calvin.walton@gmail.com>

Re: Spurious completions during NCQ

[Hugo Mills]

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On Fri, Feb 15, 2008 at 10:00:00AM -0500, Calvin Walton wrote:
> On Fri, 2008-02-15 at 13:46 +0000, Hugo Mills wrote:
> > I'm getting these on my Dell Latitude D830:
> > 
> > Feb 15 13:06:00 willow kernel: ata1.00: exception Emask 0x2 SAct 0x4 SErr 0x0 action 0x2 frozen
> > Feb 15 13:06:00 willow kernel: ata1.00: spurious completions during NCQ issue=0x0 SAct=0x4 FIS=004040a1:00000002
> 
> >    In some cases, there are several cmd/res lines listed. It's
> > happening about once an hour or so (not correlated with any other
> > event that I can see). It doesn't seem to be affecting operation of
> > the machine, but it's making me nervous.
> > 
> >    Can anyone set my mind at rest? (Or suggest a fix?)
> 
> You didn't mention which SATA chipset your laptop has, but some quick
> googling says that it's AHCI. Until 2.6.24, the AHCI driver has a
> problem where it'll report superious NCQ completions due to a bug in the
> driver logic.
> 
> > uname -a reports:
> > Linux willow 2.6.23.1-hrt3 #1 SMP Sun Nov 4 14:51:20 GMT 2007 x86_64 GNU/Linux
> 
> The fix is simple, upgrade your kernel to 2.6.24 :)

   Excellent. Thank you for clearing this up for me. I'll head off and
do the upgrade now.

   Hugo.

-- 
=== Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk ===
  PGP key: 515C238D from wwwkeys.eu.pgp.net or http://www.carfax.org.uk
    --- All mushrooms are edible,  but some are only edible once. ---    

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Re: Spurious completions during NCQ

[Michael Tokarev]

Hugo Mills wrote:
> On Fri, Feb 15, 2008 at 10:00:00AM -0500, Calvin Walton wrote:
>> On Fri, 2008-02-15 at 13:46 +0000, Hugo Mills wrote:
>>> I'm getting these on my Dell Latitude D830:
>>>
>>> Feb 15 13:06:00 willow kernel: ata1.00: exception Emask 0x2 SAct 0x4 SErr 0x0 action 0x2 frozen
>>> Feb 15 13:06:00 willow kernel: ata1.00: spurious completions during NCQ issue=0x0 SAct=0x4 FIS=004040a1:00000002
>>>    In some cases, there are several cmd/res lines listed. It's
>>> happening about once an hour or so (not correlated with any other
>>> event that I can see). It doesn't seem to be affecting operation of
>>> the machine, but it's making me nervous.

JFYI: Most probably it is correlated with smartd asking
the device for it's SMART status.

/mjt

Re: Spurious completions during NCQ

[Mark Lord]

Hugo Mills wrote:
>    I'm getting these on my Dell Latitude D830:
> 
> Feb 15 13:06:00 willow kernel: ata1.00: exception Emask 0x2 SAct 0x4 SErr 0x0 action 0x2 frozen
> Feb 15 13:06:00 willow kernel: ata1.00: spurious completions during NCQ issue=0x0 SAct=0x4 FIS=004040a1:00000002
> Feb 15 13:06:00 willow kernel: ata1.00: cmd 61/10:10:26:fb:c4/00:00:02:00:00/40 tag 2 cdb 0x0 data 8192 out
> Feb 15 13:06:00 willow kernel:          res 40/00:10:26:fb:c4/00:00:02:00:00/40 Emask 0x2 (HSM violation)
> Feb 15 13:06:00 willow kernel: ata1: soft resetting port
> Feb 15 13:06:00 willow kernel: ata1: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
> Feb 15 13:06:00 willow kernel: ata1.00: configured for UDMA/133
> Feb 15 13:06:00 willow kernel: ata1: EH complete
> Feb 15 13:06:00 willow kernel: sd 0:0:0:0: [sda] 312581808 512-byte hardware sectors (160042 MB)
> Feb 15 13:06:00 willow kernel: sd 0:0:0:0: [sda] Write Protect is off
> Feb 15 13:06:00 willow kernel: sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00
> Feb 15 13:06:00 willow kernel: sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
> 
>    In some cases, there are several cmd/res lines listed. It's
> happening about once an hour or so (not correlated with any other
> event that I can see). It doesn't seem to be affecting operation of
> the machine, but it's making me nervous.
> 
>    Can anyone set my mind at rest? (Or suggest a fix?)
..

Tejun, have the spurious completion fixes been backported
to 2.6.23 / 2.6.22 yet ?  Those kernels will be in common use
for some time to come, and this fix is more or less essential.

???

Re: Spurious completions during NCQ

[Tejun Heo]

Mark Lord wrote:
> Tejun, have the spurious completion fixes been backported
> to 2.6.23 / 2.6.22 yet ?  Those kernels will be in common use
> for some time to come, and this fix is more or less essential.

Not that I know of.  I'm prepping patches now.

Thanks.

-- 
tejun

Re: Spurious completions during NCQ

[Tejun Heo]

Tejun Heo wrote:
> Mark Lord wrote:
>> Tejun, have the spurious completion fixes been backported
>> to 2.6.23 / 2.6.22 yet ?  Those kernels will be in common use
>> for some time to come, and this fix is more or less essential.
> 
> Not that I know of.  I'm prepping patches now.
> 

Oh... it already happened in 2.6.22.15 and 2.6.23.10.  Nice.

-- 
tejun