Re: libATA SATA errors on DVD bad sectors...

[Robert Hancock <hancockrwd@gmail.com>]

On 09/22/2009 07:11 AM, Mikael Pettersson wrote:
> (cc: linux-ide added)
>
> =?UTF-8?Q?Maciej_=C5=BBenczykowski?= writes:
>   >  I'm getting the following on bad sectors on a pretty badly scratched DVD:
>   >
>   >  Sep 21 20:23:20 zeus kernel: ata12.00: exception Emask 0x0 SAct 0x0
>   >  SErr 0x0 action 0x6
>   >  Sep 21 20:23:20 zeus kernel: ata12.00: port_status 0x20280000
>
> Later you write that ata12 connects to a Promise SATA300 TX4.
> In that case, port_status 0x20280000 means:
> - Overrun Error
> - Drive Error
> - Packet Command Cycle
> which means that the drive set its error status flag and raised an interrupt
> which prematurely terminated a data transfer.
>
>   >  Sep 21 20:23:20 zeus kernel: ata12.00: cmd
>   >  a0/01:00:00:00:08/00:00:00:00:00/a0 tag 0 dma 2048 in
>   >  Sep 21 20:23:20 zeus kernel:         cdb a8 00 00 16 02 6c 00 00  00
>   >  01 00 00 00 00 00 00
>   >  Sep 21 20:23:20 zeus kernel:         res
>   >  51/30:03:00:00:00/00:00:00:00:00/e0 Emask 0x2 (HSM violation)
>   >  Sep 21 20:23:20 zeus kernel: ata12.00: status: { DRDY ERR }
>   >  Sep 21 20:23:20 zeus kernel: ata12: hard resetting link
>   >  Sep 21 20:23:21 zeus kernel: ata12: SATA link up 1.5 Gbps (SStatus 113
>   >  SControl 300)
>   >  Sep 21 20:23:21 zeus kernel: ata12.00: configured for UDMA/100
>   >  Sep 21 20:23:21 zeus kernel: ata12: EH complete
>   >
>   >  Sep 21 20:23:24 zeus kernel: ata12.00: exception Emask 0x0 SAct 0x0
>   >  SErr 0x0 action 0x6
>   >  Sep 21 20:23:24 zeus kernel: ata12.00: port_status 0x20280000
>   >  Sep 21 20:23:24 zeus kernel: ata12.00: cmd
>   >  a0/01:00:00:00:08/00:00:00:00:00/a0 tag 0 dma 2048 in
>   >  Sep 21 20:23:24 zeus kernel:         cdb a8 00 00 16 02 6d 00 00  00
>   >  01 00 00 00 00 00 00
>   >  Sep 21 20:23:24 zeus kernel:         res
>   >  51/30:03:00:00:00/00:00:00:00:00/e0 Emask 0x2 (HSM violation)
>   >  Sep 21 20:23:24 zeus kernel: ata12.00: status: { DRDY ERR }
>   >  Sep 21 20:23:24 zeus kernel: ata12: hard resetting link
>   >  Sep 21 20:23:24 zeus kernel: ata12: SATA link up 1.5 Gbps (SStatus 113
>   >  SControl 300)
>   >  Sep 21 20:23:25 zeus kernel: ata12.00: configured for UDMA/100
>   >  Sep 21 20:23:25 zeus kernel: ata12: EH complete
>   >
>   >  The command being run is:
>   >  sg_dd blk_sgio=1 bpt=1 bs=2048 cdbsz=12 coe=0 coe_limit=0 if=/dev/srX
>   >  odir of=badsector.bin count=1 skip=$i
>   >
>   >  on a Fedora 11 box:
>   >  Linux zeus 2.6.30.5-43.fc11.x86_64 #1 SMP Thu Aug 27 21:39:52 EDT 2009
>   >  x86_64 x86_64 x86_64 GNU/Linux
>   >
>   >  These only seem to show up when the DVD is inserted into /dev/sr1.
>   >  /dev/sr0 doesn't seem to spew this crap (although both drives fail to
>   >  read the sector).
>   >
>   >  /sys/block/sr0 ->
>   >  ../devices/pci0000:00/0000:00:1f.2/host0/target0:0:0/0:0:0:0/block/sr0
>   >  /sys/block/sr1 ->
>   >  ../devices/pci0000:00/0000:00:1e.0/0000:03:09.0/host11/target11:0:0/11:0:0:0/block/sr1
>   >
>   >  ata1.00: HL-DT-ST BD-RE GGW-H20L YL05 UDMA/133
>   >  ata12.00: LITE-ON DVDRW LH-20A1L BL06 UDMA/100
>   >
>   >  # lspci [-n] | egrep '1e.0|1f.2|3:09'
>   >  00:1f.2 0106: 8086:2922 SATA controller: Intel Corporation
>   >  82801IR/IO/IH (ICH9R/DO/DH) 6 port SATA AHCI Controller (rev 02)
>   >  00:1e.0 0604: 8086:244e PCI bridge: Intel Corporation 82801 PCI Bridge (rev 92)
>   >  03:09.0 0180: 105a:3d17 Mass storage controller: Promise Technology,
>   >  Inc. PDC40718 (SATA 300 TX4) (rev 02)
>   >
>   >  ie. the Lite-On drive on the promise TX4 controller has issues, while
>   >  the LG on the intel AHCI controller seems fine...
>
> The obvious next experiment would be to swap the drives and see how
> the Lite-On behaves on the ICH9 and the LG behaves on the TX4.
>
>   >  Would it make sense to add this somewhere into the code as a 'bad
>   >  sector' error condition and not perform a hard reset?
>
> The sata_promise driver upon seeing the port_status above sets
> AC_ERR_HSM and AC_ERR_DEV, and performs a soft reset. Apparently
> libata-eh follows up with a hard(er) reset, which doesn't surprise
> me given the HSM and DEV errors.

This port status likely should not be an HSM error if it can occur as a 
result of a normal media error. HSM error is supposed to be for cases 
where the drive indicates a status that's illegal or makes no sense, 
etc. and will trigger a reset which shouldn't be needed in this case..

>
>   >  It may be worth pointing out that the LiteOn drive is significantly
>   >  faster in dealing with the bad sectors, and actually successfully
>   >  reads a far larger number of them (about 15% of the sectors that the
>   >  LG can't read, the Lite-On can, and in about 2/3 of the time).  I
>   >  would guess that if it didn't have to hard reset the bus, it'd be even
>   >  faster...
>
> So things actually work Ok with the Lite-On on the TX4, and you're mainly
> concerned about log messages and potential performance loss?
>
> /Mikael
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