Port Multiplier Patch 2.6.22.1 on Alpha

Port Multiplier Patch 2.6.22.1 on Alpha

[Tom Evans]

Hi Tejun and all -

I have applied the libata-tj-stable patch to the 2.6.22.1 kernel and am 
having some issues.
I'm not certain if it is the PMP patches, or my platform.

I have a Silicon Images 3124-2 based PCI-X card (Norco 4618) for my 
Alpha system .
I realize this is not the usual test platform and I understand if you 
decide to blame it on the platform.

I also have a "StorBox" which is a 5-bay eSATA box based with the Si4276 
port multiplier, which is noted to be "quirky" in the README.

The problem arises when I try to create/assemble a linux software raid 
using 4 disks (level 6).  At the time the system becomes very very slow 
- basically unresponsive - I can get an occasional keystroke in on the 
console, but the machine is essentially dead.

If I pull the eSATAcable out of the card, the sata_si24 driver does its 
thing and the machine comes back to life.
The unit is plugged into the port designated as the first - all drive 
bays contain a drive.

I am able to individually address and to format individual drives 
without performance issue, but the creation of a raid is deadly ....

Have you heard of such and issue with the 3124-2/4276 combination?
Is anyone else trying this driver on an Alpha?

I have similar such behavior before when using drivers that generate 
many unaligned accesses - I only have seen 2 places they occur in 
sata_sil24 and have fixed them myself, but that made no difference.

Are there any logs or output that might help?  Should I attempt to 
upgrade the firmware of the devices?

Thanks,
...tom

Re: Port Multiplier Patch 2.6.22.1 on Alpha

[Jeff Garzik]

Tom Evans wrote:
> Have you heard of such and issue with the 3124-2/4276 combination?
> Is anyone else trying this driver on an Alpha?

Alpha should not be operationally much different from other little 
endian 64-bit platforms.

The PCI swizzle might be weird (what is your Alpha platform?), is the 
only Alpha-specific thing that comes to mind.


> I have similar such behavior before when using drivers that generate 
> many unaligned accesses - I only have seen 2 places they occur in 
> sata_sil24 and have fixed them myself, but that made no difference.

We definitely want to fix all these you find.  Please post more info...

Also, if you are highly motivated, I would love to see if other SATA 
cards have similar problems on Alpha...

	Jeff

Re: Port Multiplier Patch 2.6.22.1 on Alpha

[Tom Evans]

Thanks for the response Jeff !

Jeff Garzik wrote:
>
> Alpha should not be operationally much different from other little 
> endian 64-bit platforms.
>
> The PCI swizzle might be weird (what is your Alpha platform?), is the 
> only Alpha-specific thing that comes to mind.
>
I am using a DS20  (Tsunami / Goldrush).
>
>> I have similar such behavior before when using drivers that generate 
>> many unaligned accesses - I only have seen 2 places they occur in 
>> sata_sil24 and have fixed them myself, but that made no difference.
>
> We definitely want to fix all these you find.  Please post more info...
>
In sil24_config_port, the writel's for /* zero error counters */ should 
be writew's - they are 16bit control registers.
Only PORT_DECODE_ERR_THRESH and PORT_CRC_ERR_THRESH appear to be 
unaligned, but why risk a stl when a stw (on platforms that support it) 
can be used.
> Also, if you are highly motivated, I would love to see if other SATA 
> cards have similar problems on Alpha...
>
I'll need to find a computer store with a decent return policy, but I 
would consider doing it ....

...tom

Re: Port Multiplier Patch 2.6.22.1 on Alpha

[Tejun Heo]

Tom Evans wrote:
> In sil24_config_port, the writel's for /* zero error counters */ should
> be writew's - they are 16bit control registers.
> Only PORT_DECODE_ERR_THRESH and PORT_CRC_ERR_THRESH appear to be
> unaligned, but why risk a stl when a stw (on platforms that support it)
> can be used.

That part of the code was taken verbatim from the Silicon Image sample
driver, which I'm sure have been tested only on x86s.  Those error
threshold feature isn't really used and using writew's should be fine.
Do things work better after changing to writew's?

-- 
tejun

Re: Port Multiplier Patch 2.6.22.1 on Alpha

[Tejun Heo]

Tom Evans wrote:
> No real performance change, but the # of unaligned kernel  goes from ~14
> to zero on my system.
> 
> It's really just cosmetic I believe.

Care to post signed-off patch?

-- 
tejun

Re: Port Multiplier Patch 2.6.22.1 on Alpha

[Tom Evans]

I have included my boot messages and an lspci, in any of the info is useful.

I do have a VIA based sata board that works well also installed - any 
potential for conflict?

...tom

-----------------
Boot Log
-----------------

[4194001.852669] Linux version 2.6.22.1-ds20 (root@chronictown) (gcc 
version 4.1.2 20061115 (prerelease) (Debian 4.1.1-21)) #1 SMP Wed Aug 29 
03:40:59 EDT 2007
[4194001.852669] Booting on Tsunami variation Goldrush using machine 
vector DP264 from SRM
[4194001.852669] Major Options: SMP LEGACY_START VERBOSE_MCHECK MAGIC_SYSRQ
[4194001.852669] Command line: ro root=/dev/sda3 ide=reverse single
[4194001.852669] memcluster 0, usage 1, start        0, end      256
[4194001.852669] memcluster 1, usage 0, start      256, end   130976
[4194001.852669] memcluster 2, usage 1, start   130976, end   131072
[4194001.852669] freeing pages 256:384
[4194001.852669] freeing pages 999:130976
[4194001.852669] reserving pages 999:1001
[4194001.852669] 4096K Bcache detected; load hit latency 20 cycles, load 
miss latency 106 cycles
[4194001.852669] Console graphics on hose 0
[4194001.852669] SMP: 2 CPUs probed -- cpu_present_map = 3
[4194001.852669] On node 0 totalpages: 130976
[4194001.852669]   DMA zone: 895 pages used for memmap
[4194001.852669]   DMA zone: 0 pages reserved
[4194001.852669]   DMA zone: 130081 pages, LIFO batch:15
[4194001.852669]   Normal zone: 0 pages used for memmap
[4194001.852669] Built 1 zonelists.  Total pages: 130081
[4194001.852669] Kernel command line: ro root=/dev/sda3 ide=reverse single
[4194001.852669] PID hash table entries: 4096 (order: 12, 32768 bytes)
[4194001.852669] Using epoch = 1952
[4194001.855599] Console: colour VGA+ 80x25
[4194001.858529] Dentry cache hash table entries: 131072 (order: 7, 
1048576 bytes)
[4194001.861459] Inode-cache hash table entries: 65536 (order: 6, 524288 
bytes)
[4194001.907357] Memory: 1029240k/1047808k available (3251k kernel code, 
15888k reserved, 225k data, 168k init)
[4194001.908333] Calibrating delay loop... 996.00 BogoMIPS (lpj=486400)
[4194001.926888] Mount-cache hash table entries: 512
[4194001.926888] SMP starting up secondaries.
[4194001.935677] Calibrating delay loop... 996.00 BogoMIPS (lpj=486400)
[4194001.954232] Brought up 2 CPUs
[4194001.954232] SMP: Total of 2 processors activated (1998.25 BogoMIPS).
[4194002.035287] migration_cost=2929
[4194002.036263] NET: Registered protocol family 16
[4194002.041146] PCI: Bridge: 0000:00:08.0
[4194002.041146]   IO window: 8000-8fff
[4194002.041146]   MEM window: 0a000000-0a0fffff
[4194002.042122]   PREFETCH window: 0a100000-0a1fffff
[4194002.042122] SMC37c669 Super I/O Controller found @ 0x3f0
[4194002.046029] Linux Plug and Play Support v0.97 (c) Adam Belay
[4194002.047005] SCSI subsystem initialized
[4194002.047005] libata version 3.00 loaded.
[4194002.048958] NET: Registered protocol family 2
[4194002.061654] IP route cache hash table entries: 8192 (order: 3, 
65536 bytes)
[4194002.061654] TCP established hash table entries: 32768 (order: 6, 
786432 bytes)
[4194002.063607] TCP bind hash table entries: 32768 (order: 6, 524288 bytes)
[4194002.065560] TCP: Hash tables configured (established 32768 bind 32768)
[4194002.065560] TCP reno registered
[4194002.069466] srm_env: version 0.0.6 loaded successfully
[4194002.071419] io scheduler noop registered
[4194002.071419] io scheduler anticipatory registered (default)
[4194002.071419] io scheduler deadline registered
[4194002.071419] isapnp: Scanning for PnP cards...
[4194002.427864] isapnp: No Plug & Play device found
[4194002.562630] rtc: Digital UNIX epoch (1952) detected
[4194002.562630] Real Time Clock Driver v1.12ac
[4194002.562630] Serial: 8250/16550 driver $Revision: 1.90 $ 4 ports, 
IRQ sharing disabled
[4194002.562630] serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
[4194002.563607] serial8250: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A
[4194002.565560] Floppy drive(s): fd0 is 2.88M
[4194002.581185] FDC 0 is a post-1991 82077
[4194002.583138] nbd: registered device at major 43
[4194002.587044] Loading iSCSI transport class v2.0-724.
[4194002.747200] sym0: <875> rev 0x4 at pci 0000:01:00.0 irq 27
[4194002.834114] sym0: Symbios NVRAM, ID 7, Fast-20, SE, parity checking
[4194002.834114] sym0: open drain IRQ line driver, using on-chip SRAM
[4194002.834114] sym0: using LOAD/STORE-based firmware.
[4194002.835091] sym0: SCSI BUS has been reset.
[4194002.841927] scsi0 : sym-2.2.3
[4194003.003059] sym1: <875> rev 0x4 at pci 0000:01:01.0 irq 26
[4194003.089974] sym1: Symbios NVRAM, ID 7, Fast-20, SE, parity checking
[4194003.089974] sym1: open drain IRQ line driver, using on-chip SRAM
[4194003.089974] sym1: using LOAD/STORE-based firmware.
[4194003.089974] sym1: SCSI BUS has been reset.
[4194003.097786] scsi1 : sym-2.2.3
[4194003.097786] sata_via 0001:02:08.0: version 2.2
[4194003.097786] sata_via 0001:02:08.0: routed to hard irq line 11
[4194003.098763] scsi2 : sata_via
[4194003.098763] scsi3 : sata_via
[4194003.098763] scsi4 : sata_via
[4194003.099739] ata1: SATA max UDMA/133 cmd 0xfffffd03fc008830 ctl 
0xfffffd03fc00883a bmdma 0xfffffd03fc008800 irq 43
[4194003.099739] ata2: SATA max UDMA/133 cmd 0xfffffd03fc008840 ctl 
0xfffffd03fc00884a bmdma 0xfffffd03fc008808 irq 43
[4194003.099739] ata3: PATA max UDMA/133 cmd 0xfffffd03fc008850 ctl 
0xfffffd03fc00885a bmdma 0xfffffd03fc008810 irq 43
[4194003.555794] ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 310)
[4194003.578255] ata1.00: ATA-7: SAMSUNG SP2504C, VT100-33, max UDMA7
[4194003.578255] ata1.00: 488397168 sectors, multi 0: LBA48 NCQ (depth 0/32)
[4194003.600715] ata1.00: configured for UDMA/133
[4194003.904426] ata2: SATA link down (SStatus 0 SControl 310)
[4194004.077278] ata3.00: ATA-7: SAMSUNG SP2514N, VF100-41, max UDMA/100
[4194004.077278] ata3.00: 488397168 sectors, multi 0: LBA48
[4194004.077278] ata3.01: ATA-7: SAMSUNG SP2514N, VF100-41, max UDMA/100
[4194004.077278] ata3.01: 488397168 sectors, multi 0: LBA48
[4194004.125129] ata3.00: configured for UDMA/100
[4194004.151496] ata3.01: configured for UDMA/100
[4194004.151496] scsi: waiting for bus probes to complete ...
[4194006.376105] scsi 1:0:1:0: Direct-Access     FUJITSU  
MAJ3091MP        5508 PQ: 0 ANSI: 4
[4194006.376105]  target1:0:1: tagged command queuing enabled, command 
queue depth 16.
[4194006.377081]  target1:0:1: Beginning Domain Validation
[4194006.377081]  target1:0:1: asynchronous
[4194006.379034]  target1:0:1: wide asynchronous
[4194006.380987]  target1:0:1: FAST-20 WIDE SCSI 40.0 MB/s ST (50 ns, 
offset 16)
[4194006.381964]  target1:0:1: Domain Validation skipping write tests
[4194006.381964]  target1:0:1: Ending Domain Validation
[4194007.007940] scsi 0:0:4:0: Sequential-Access ARCHIVE  Python 
04106-XXX 743B PQ: 0 ANSI: 2
[4194007.007940]  target0:0:4: Beginning Domain Validation
[4194007.012823]  target0:0:4: asynchronous
[4194007.033331]  target0:0:4: FAST-10 SCSI 10.0 MB/s ST (100 ns, offset 15)
[4194007.046026]  target0:0:4: Domain Validation skipping write tests
[4194007.046026]  target0:0:4: Ending Domain Validation
[4194010.026493] scsi 0:0:4:0: Attached scsi generic sg0 type 1
[4194010.209110] sd 1:0:1:0: [sda] 17783239 512-byte hardware sectors 
(9105 MB)
[4194010.212040] sd 1:0:1:0: [sda] Write Protect is off
[4194010.212040] sd 1:0:1:0: [sda] Mode Sense: ab 00 10 08
[4194010.213993] sd 1:0:1:0: [sda] Write cache: enabled, read cache: 
enabled, supports DPO and FUA
[4194010.214970] sd 1:0:1:0: [sda] 17783239 512-byte hardware sectors 
(9105 MB)
[4194010.217900] sd 1:0:1:0: [sda] Write Protect is off
[4194010.217900] sd 1:0:1:0: [sda] Mode Sense: ab 00 10 08
[4194010.218876] sd 1:0:1:0: [sda] Write cache: enabled, read cache: 
enabled, supports DPO and FUA
[4194010.219853]  sda: sda1 sda2 sda3 sda4
[4194010.228642] sd 1:0:1:0: [sda] Attached SCSI disk
[4194010.229618] sd 1:0:1:0: Attached scsi generic sg1 type 0
[4194010.229618] scsi 2:0:0:0: Direct-Access     ATA      SAMSUNG 
SP2504C  VT10 PQ: 0 ANSI: 5
[4194010.230595] sd 2:0:0:0: [sdb] 488397168 512-byte hardware sectors 
(250059 MB)
[4194010.230595] sd 2:0:0:0: [sdb] Write Protect is off
[4194010.230595] sd 2:0:0:0: [sdb] Mode Sense: 00 3a 00 00
[4194010.230595] sd 2:0:0:0: [sdb] Write cache: enabled, read cache: 
enabled, doesn't support DPO or FUA
[4194010.231571] sd 2:0:0:0: [sdb] 488397168 512-byte hardware sectors 
(250059 MB)
[4194010.231571] sd 2:0:0:0: [sdb] Write Protect is off
[4194010.231571] sd 2:0:0:0: [sdb] Mode Sense: 00 3a 00 00
[4194010.231571] sd 2:0:0:0: [sdb] Write cache: enabled, read cache: 
enabled, doesn't support DPO or FUA
[4194010.231571]  sdb: sdb1
[4194010.235478] sd 2:0:0:0: [sdb] Attached SCSI disk
[4194010.236454] sd 2:0:0:0: Attached scsi generic sg2 type 0
[4194010.236454] scsi 4:0:0:0: Direct-Access     ATA      SAMSUNG 
SP2514N  VF10 PQ: 0 ANSI: 5
[4194010.237431] sd 4:0:0:0: [sdc] 488397168 512-byte hardware sectors 
(250059 MB)
[4194010.237431] sd 4:0:0:0: [sdc] Write Protect is off
[4194010.237431] sd 4:0:0:0: [sdc] Mode Sense: 00 3a 00 00
[4194010.237431] sd 4:0:0:0: [sdc] Write cache: enabled, read cache: 
enabled, doesn't support DPO or FUA
[4194010.237431] sd 4:0:0:0: [sdc] 488397168 512-byte hardware sectors 
(250059 MB)
[4194010.238407] sd 4:0:0:0: [sdc] Write Protect is off
[4194010.238407] sd 4:0:0:0: [sdc] Mode Sense: 00 3a 00 00
[4194010.238407] sd 4:0:0:0: [sdc] Write cache: enabled, read cache: 
enabled, doesn't support DPO or FUA
[4194010.238407]  sdc: sdc1
[4194010.249150] sd 4:0:0:0: [sdc] Attached SCSI disk
[4194010.249150] sd 4:0:0:0: Attached scsi generic sg3 type 0
[4194010.250126] scsi 4:0:1:0: Direct-Access     ATA      SAMSUNG 
SP2514N  VF10 PQ: 0 ANSI: 5
[4194010.250126] sd 4:0:1:0: [sdd] 488397168 512-byte hardware sectors 
(250059 MB)
[4194010.250126] sd 4:0:1:0: [sdd] Write Protect is off
[4194010.251103] sd 4:0:1:0: [sdd] Mode Sense: 00 3a 00 00
[4194010.251103] sd 4:0:1:0: [sdd] Write cache: enabled, read cache: 
enabled, doesn't support DPO or FUA
[4194010.251103] sd 4:0:1:0: [sdd] 488397168 512-byte hardware sectors 
(250059 MB)
[4194010.251103] sd 4:0:1:0: [sdd] Write Protect is off
[4194010.251103] sd 4:0:1:0: [sdd] Mode Sense: 00 3a 00 00
[4194010.251103] sd 4:0:1:0: [sdd] Write cache: enabled, read cache: 
enabled, doesn't support DPO or FUA
[4194010.252079]  sdd: sdd1
[4194010.255985] sd 4:0:1:0: [sdd] Attached SCSI disk
[4194010.256962] sd 4:0:1:0: Attached scsi generic sg4 type 0
[4194010.261845] serio: i8042 KBD port at 0x60,0x64 irq 1
[4194010.261845] serio: i8042 AUX port at 0x60,0x64 irq 12
[4194010.262821] mice: PS/2 mouse device common for all mice
[4194010.818485] input: AT Raw Set 2 keyboard as /class/input/input0
[4194010.834110] atkbd.c: keyboard reset failed on isa0060/serio1
[4194010.864384] md: linear personality registered for level -1
[4194010.864384] md: raid0 personality registered for level 0
[4194010.864384] md: raid1 personality registered for level 1
[4194010.864384] md: raid10 personality registered for level 10
[4194010.880985] raid6: int64x1    464 MB/s
[4194010.900516] raid6: int64x2    624 MB/s
[4194010.917118] raid6: int64x4    736 MB/s
[4194010.933719] raid6: int64x8    460 MB/s
[4194010.933719] raid6: using algorithm int64x4 (736 MB/s)
[4194010.933719] md: raid6 personality registered for level 6
[4194010.933719] md: raid5 personality registered for level 5
[4194010.933719] md: raid4 personality registered for level 4
[4194010.933719] raid5: automatically using best checksumming function: 
alpha prefetch
[4194010.938602]    alpha prefetch:  2072.576 MB/sec
[4194010.938602] raid5: using function: alpha prefetch (2072.576 MB/sec)
[4194010.938602] md: multipath personality registered for level -4
[4194010.938602] md: faulty personality registered for level -5
[4194010.938602] TCP cubic registered
[4194010.938602] NET: Registered protocol family 1
[4194010.938602] NET: Registered protocol family 10
[4194010.939579] lo: Disabled Privacy Extensions
[4194010.939579] NET: Registered protocol family 17
[4194010.940555] md: Autodetecting RAID arrays.
[4194011.008915] md: autorun ...
[4194011.008915] md: considering sdd1 ...
[4194011.008915] md:  adding sdd1 ...
[4194011.008915] md:  adding sdc1 ...
[4194011.008915] md:  adding sdb1 ...
[4194011.009891] md: created md1
[4194011.009891] md: bind<sdb1>
[4194011.009891] md: bind<sdc1>
[4194011.009891] md: bind<sdd1>
[4194011.009891] md: running: <sdd1><sdc1><sdb1>
[4194011.009891] raid5: device sdd1 operational as raid disk 2
[4194011.009891] raid5: device sdc1 operational as raid disk 1
[4194011.010868] raid5: device sdb1 operational as raid disk 0
[4194011.011844] raid5: allocated 6284kB for md1
[4194011.011844] raid5: raid level 5 set md1 active with 3 out of 3 
devices, algorithm 2
[4194011.011844] RAID5 conf printout:
[4194011.011844]  --- rd:3 wd:3
[4194011.011844]  disk 0, o:1, dev:sdb1
[4194011.012821]  disk 1, o:1, dev:sdc1
[4194011.012821]  disk 2, o:1, dev:sdd1
[4194011.012821] md: ... autorun DONE.
[4194011.025516] EXT3-fs: INFO: recovery required on readonly filesystem.
[4194011.025516] EXT3-fs: write access will be enabled during recovery.
[4194013.237429] kjournald starting.  Commit interval 5 seconds
[4194013.237429] EXT3-fs: recovery complete.
[4194013.238406] EXT3-fs: mounted filesystem with ordered data mode.
[4194013.238406] VFS: Mounted root (ext3 filesystem) readonly.
[4194013.239382] Freeing unused kernel memory: 168k freed
[4194016.854615] Adding 1976560k swap on /dev/sda4.  Priority:-1 
extents:1 across:1976560k
[4194017.176880] EXT3 FS on sda3, internal journal
[4194018.601684] Uniform Multi-Platform E-IDE driver Revision: 7.00alpha2
[4194018.601684] ide: Assuming 33MHz system bus speed for PIO modes; 
override with idebus=xx
[4194018.942504] device-mapper: ioctl: 4.11.0-ioctl (2006-10-12) 
initialised: dm-devel@redhat.com
[4194030.097772] kjournald starting.  Commit interval 5 seconds
[4194030.111444] EXT3 FS on md1, internal journal
[4194030.111444] EXT3-fs: mounted filesystem with ordered data mode.
[4194031.476678] VIA Networking Velocity Family Gigabit Ethernet Adapter 
Driver Ver. 1.14
[4194031.476678] Copyright (c) 2002, 2003 VIA Networking Technologies, Inc.
[4194031.477654] Copyright (c) 2004 Red Hat Inc.
[4194031.489373] eth0: VIA Networking Velocity Family Gigabit Ethernet 
Adapter
[4194031.489373] eth0: Ethernet Address: 00:13:49:12:44:DD
[4194032.070427] sata_sil24 0001:02:07.0: version 1.0
[4194032.071404] scsi5 : sata_sil24
[4194032.075310] scsi6 : sata_sil24
[4194032.097771] scsi7 : sata_sil24
[4194032.115349] scsi8 : sata_sil24
[4194032.140740] ata4: SATA max UDMA/100 cmd 0xfffffd0209080000 ctl 
0x0000000000000000 bmdma 0x0000000000000000 irq 47
[4194032.140740] ata5: SATA max UDMA/100 cmd 0xfffffd0209082000 ctl 
0x0000000000000000 bmdma 0x0000000000000000 irq 47
[4194032.140740] ata6: SATA max UDMA/100 cmd 0xfffffd0209084000 ctl 
0x0000000000000000 bmdma 0x0000000000000000 irq 47
[4194032.140740] ata7: SATA max UDMA/100 cmd 0xfffffd0209086000 ctl 
0x0000000000000000 bmdma 0x0000000000000000 irq 47
[4194034.306754] ata4: SATA link up 3.0 Gbps (SStatus 123 SControl 0)
[4194034.408317] ata4.15: Port Multiplier 1.1, 0x1095:0x4726 r31, 7 
ports, feat 0x1/0x9
[4194034.509879] ata4.00: hard resetting link
[4194035.008902] ata4.00: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
[4194035.021598] ata4.01: hard resetting link
[4194035.623160] ata4.01: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
[4194035.635855] ata4.02: hard resetting link
[4194036.172964] ata4.02: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
[4194036.185660] ata4.03: hard resetting link
[4194036.710073] ata4.03: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
[4194036.722769] ata4.04: hard resetting link
[4194037.259878] ata4.04: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
[4194037.259878] ata4.05: hard resetting link
[4194037.758901] ata4.05: SATA link up 3.0 Gbps (SStatus 123 SControl 0)
[4194037.758901] ata4.06: hard resetting link
[4194038.257924] ata4.06: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
[4194038.280385] ata4.00: ATA-7: WDC WD4000AAKS-00TMA0, 12.01C01, max 
UDMA/133
[4194038.280385] ata4.00: 781422768 sectors, multi 0: LBA48 NCQ (depth 
31/32)
[4194038.281362] ata4.00: configured for UDMA/100
[4194038.286245] ata4.01: ATA-7: SAMSUNG SP2504C, VT100-33, max UDMA7
[4194038.286245] ata4.01: 488397168 sectors, multi 0: LBA48 NCQ (depth 
31/32)
[4194038.292104] ata4.01: configured for UDMA/100
[4194038.299916] ata4.02: ATA-7: WDC WD4000AAKS-00TMA0, 12.01C01, max 
UDMA/133
[4194038.299916] ata4.02: 781422768 sectors, multi 0: LBA48 NCQ (depth 
31/32)
[4194038.300893] ata4.02: configured for UDMA/100
[4194038.329213] ata4.03: ATA-7: WDC WD4000AAKS-00TMA0, 12.01C01, max 
UDMA/133
[4194038.329213] ata4.03: 781422768 sectors, multi 0: LBA48 NCQ (depth 
31/32)
[4194038.330190] ata4.03: configured for UDMA/100
[4194038.338002] ata4.04: ATA-7: WDC WD4000AAKS-00TMA0, 12.01C01, max 
UDMA/133
[4194038.338002] ata4.04: 781422768 sectors, multi 0: LBA48 NCQ (depth 
31/32)
[4194038.338979] ata4.04: configured for UDMA/100
[4194038.338979] ata4.05: ATA-6: Config  Disk, PLS12052, max UDMA/133
[4194038.338979] ata4.05: 640 sectors, multi 1: LBA
[4194038.338979] ata4.05: device is on DMA blacklist, disabling DMA
[4194038.338979] ata4.05: configured for PIO4
[4194038.364370] ata4: EH complete
[4194040.415150] ata5: SATA link down (SStatus 0 SControl 0)
[4194042.465930] ata6: SATA link down (SStatus 0 SControl 0)
[4194044.516710] ata7: SATA link down (SStatus 0 SControl 0)
[4194044.516710] scsi 5:0:0:0: Direct-Access     ATA      WDC 
WD4000AAKS-0 12.0 PQ: 0 ANSI: 5
[4194044.529405] sd 5:0:0:0: [sde] 781422768 512-byte hardware sectors 
(400088 MB)
[4194044.529405] sd 5:0:0:0: [sde] Write Protect is off
[4194044.529405] sd 5:0:0:0: [sde] Mode Sense: 00 3a 00 00
[4194044.529405] sd 5:0:0:0: [sde] Write cache: enabled, read cache: 
enabled, doesn't support DPO or FUA
[4194044.530382] sd 5:0:0:0: [sde] 781422768 512-byte hardware sectors 
(400088 MB)
[4194044.530382] sd 5:0:0:0: [sde] Write Protect is off
[4194044.530382] sd 5:0:0:0: [sde] Mode Sense: 00 3a 00 00
[4194044.530382] sd 5:0:0:0: [sde] Write cache: enabled, read cache: 
enabled, doesn't support DPO or FUA
[4194044.530382]  sde: sde1
[4194044.578234] sd 5:0:0:0: [sde] Attached SCSI disk
[4194044.593859] sd 5:0:0:0: Attached scsi generic sg5 type 0
[4194044.608507] scsi 5:1:0:0: Direct-Access     ATA      SAMSUNG 
SP2504C  VT10 PQ: 0 ANSI: 5
[4194044.656358] sd 5:1:0:0: [sdf] 488397168 512-byte hardware sectors 
(250059 MB)
[4194044.657335] sd 5:1:0:0: [sdf] Write Protect is off
[4194044.657335] sd 5:1:0:0: [sdf] Mode Sense: 00 3a 00 00
[4194044.671007] sd 5:1:0:0: [sdf] Write cache: enabled, read cache: 
enabled, doesn't support DPO or FUA
[4194044.672960] sd 5:1:0:0: [sdf] 488397168 512-byte hardware sectors 
(250059 MB)
[4194044.673937] sd 5:1:0:0: [sdf] Write Protect is off
[4194044.673937] sd 5:1:0:0: [sdf] Mode Sense: 00 3a 00 00
[4194044.677843] sd 5:1:0:0: [sdf] Write cache: enabled, read cache: 
enabled, doesn't support DPO or FUA
[4194044.677843]  sdf: sdf1
[4194044.707140] sd 5:1:0:0: [sdf] Attached SCSI disk
[4194044.727648] sd 5:1:0:0: Attached scsi generic sg6 type 0
[4194044.755968] scsi 5:2:0:0: Direct-Access     ATA      WDC 
WD4000AAKS-0 12.0 PQ: 0 ANSI: 5
[4194044.787218] sd 5:2:0:0: [sdg] 781422768 512-byte hardware sectors 
(400088 MB)
[4194044.788194] sd 5:2:0:0: [sdg] Write Protect is off
[4194044.788194] sd 5:2:0:0: [sdg] Mode Sense: 00 3a 00 00
[4194044.805772] sd 5:2:0:0: [sdg] Write cache: enabled, read cache: 
enabled, doesn't support DPO or FUA
[4194044.807726] sd 5:2:0:0: [sdg] 781422768 512-byte hardware sectors 
(400088 MB)
[4194044.808702] sd 5:2:0:0: [sdg] Write Protect is off
[4194044.808702] sd 5:2:0:0: [sdg] Mode Sense: 00 3a 00 00
[4194044.816515] sd 5:2:0:0: [sdg] Write cache: enabled, read cache: 
enabled, doesn't support DPO or FUA
[4194044.816515]  sdg: sdg1
[4194044.843858] sd 5:2:0:0: [sdg] Attached SCSI disk
[4194044.856554] sd 5:2:0:0: Attached scsi generic sg7 type 0
[4194044.859483] scsi 5:3:0:0: Direct-Access     ATA      WDC 
WD4000AAKS-0 12.0 PQ: 0 ANSI: 5
[4194044.914171] sd 5:3:0:0: [sdh] 781422768 512-byte hardware sectors 
(400088 MB)
[4194044.915147] sd 5:3:0:0: [sdh] Write Protect is off
[4194044.915147] sd 5:3:0:0: [sdh] Mode Sense: 00 3a 00 00
[4194044.917101] sd 5:3:0:0: [sdh] Write cache: enabled, read cache: 
enabled, doesn't support DPO or FUA
[4194044.919054] sd 5:3:0:0: [sdh] 781422768 512-byte hardware sectors 
(400088 MB)
[4194044.947374] sd 5:3:0:0: [sdh] Write Protect is off
[4194044.947374] sd 5:3:0:0: [sdh] Mode Sense: 00 3a 00 00
[4194044.949327] sd 5:3:0:0: [sdh] Write cache: enabled, read cache: 
enabled, doesn't support DPO or FUA
[4194044.949327]  sdh: sdh1
[4194044.974718] sd 5:3:0:0: [sdh] Attached SCSI disk
[4194044.997179] sd 5:3:0:0: Attached scsi generic sg8 type 0
[4194045.019640] scsi 5:4:0:0: Direct-Access     ATA      WDC 
WD4000AAKS-0 12.0 PQ: 0 ANSI: 5
[4194045.055772] sd 5:4:0:0: [sdi] 781422768 512-byte hardware sectors 
(400088 MB)
[4194045.056749] sd 5:4:0:0: [sdi] Write Protect is off
[4194045.056749] sd 5:4:0:0: [sdi] Mode Sense: 00 3a 00 00
[4194045.058702] sd 5:4:0:0: [sdi] Write cache: enabled, read cache: 
enabled, doesn't support DPO or FUA
[4194045.060655] sd 5:4:0:0: [sdi] 781422768 512-byte hardware sectors 
(400088 MB)
[4194045.061632] sd 5:4:0:0: [sdi] Write Protect is off
[4194045.061632] sd 5:4:0:0: [sdi] Mode Sense: 00 3a 00 00
[4194045.063585] sd 5:4:0:0: [sdi] Write cache: enabled, read cache: 
enabled, doesn't support DPO or FUA
[4194045.063585]  sdi: sdi1
[4194045.132921] sd 5:4:0:0: [sdi] Attached SCSI disk
[4194045.180772] sd 5:4:0:0: Attached scsi generic sg9 type 0
[4194045.181749] scsi 5:5:0:0: Direct-Access     ATA      Config  
Disk     PLS1 PQ: 0 ANSI: 5
[4194045.230577] sd 5:5:0:0: [sdj] 640 512-byte hardware sectors (0 MB)
[4194045.231553] sd 5:5:0:0: [sdj] Write Protect is off
[4194045.231553] sd 5:5:0:0: [sdj] Mode Sense: 00 3a 00 00
[4194045.233507] sd 5:5:0:0: [sdj] Write cache: disabled, read cache: 
enabled, doesn't support DPO or FUA
[4194045.235460] sd 5:5:0:0: [sdj] 640 512-byte hardware sectors (0 MB)
[4194045.236436] sd 5:5:0:0: [sdj] Write Protect is off
[4194045.236436] sd 5:5:0:0: [sdj] Mode Sense: 00 3a 00 00
[4194045.238389] sd 5:5:0:0: [sdj] Write cache: disabled, read cache: 
enabled, doesn't support DPO or FUA
[4194045.238389]  sdj: unknown partition table
[4194045.246202] sd 5:5:0:0: [sdj] Attached SCSI disk
[4194045.290147] sd 5:5:0:0: Attached scsi generic sg10 type 0
[4194047.348740] usbcore: registered new interface driver usbfs
[4194047.361435] usbcore: registered new interface driver hub
[4194047.376084] usbcore: registered new device driver usb
[4194047.403427] ohci_hcd: 2006 August 04 USB 1.1 'Open' Host Controller 
(OHCI) Driver
[4194047.416123] ohci_hcd 0000:00:05.3: OHCI Host Controller
[4194047.445420] ohci_hcd 0000:00:05.3: new USB bus registered, assigned 
bus number 1
[4194047.445420] ohci_hcd 0000:00:05.3: irq 10, io mem 0x0a240000
[4194047.526474] usb usb1: configuration #1 chosen from 1 choice
[4194047.538193] hub 1-0:1.0: USB hub found
[4194047.538193] hub 1-0:1.0: 2 ports detected
[4194050.142684] st: Version 20070203, fixed bufsize 32768, s/g segs 256
[4194050.288192] st 0:0:4:0: Attached scsi tape st0
[4194050.289168] st 0:0:4:0: st0: try direct i/o: yes (alignment 512 B)
[4194050.405379] st0: Block limits 1 - 16777215 bytes.
[4194051.690535] Velocity is AUTO mode
[4194051.699324] ADDRCONF(NETDEV_UP): eth0: link is not ready
[4194054.969830] eth0: Link auto-negotiation speed 1000M bps full duplex
[4194054.973736] ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready
[4194065.336035] eth0: no IPv6 routers present



-----------------
lspci
-----------------

0000:00:05.0 ISA bridge: Contaq Microsystems 82c693
    Flags: bus master, medium devsel, latency 0

0000:00:05.1 IDE interface: Contaq Microsystems 82c693 (prog-if 80 [Master])
    Flags: bus master, medium devsel, latency 0, IRQ 14
    I/O ports at 01f0 [size=8]
    I/O ports at 03f4 [size=1]
    [virtual] Memory at 00000170 (32-bit, non-prefetchable) [disabled] 
[size=8]
    [virtual] Memory at 00000370 (type 3, non-prefetchable) [disabled] 
[size=1]
    I/O ports at 9000 [size=16]

0000:00:05.2 IDE interface: Contaq Microsystems 82c693 (prog-if 00 [])
    Flags: bus master, medium devsel, latency 0, IRQ 15
    I/O ports at 01f0 [size=8]
    I/O ports at 03f4 [size=1]
    [virtual] Memory at 00000170 (32-bit, non-prefetchable) [disabled] 
[size=8]
    [virtual] Memory at 00000370 (type 3, non-prefetchable) [disabled] 
[size=1]
    Memory at 0a220000 (32-bit, non-prefetchable) [disabled] [size=64K]

0000:00:05.3 USB Controller: Contaq Microsystems 82c693 (prog-if 10 [OHCI])
    Flags: bus master, medium devsel, latency 248, IRQ 10
    Memory at 0a240000 (32-bit, non-prefetchable) [size=4K]

0000:00:07.0 VGA compatible controller: Texas Instruments TVP4020 
[Permedia 2] (rev 01) (prog-if 00 [VGA])
    Subsystem: Elsa AG GLoria Synergy
    Flags: bus master, medium devsel, latency 255, IRQ 31
    Memory at 0a200000 (32-bit, non-prefetchable) [size=128K]
    Memory at 09000000 (32-bit, non-prefetchable) [size=8M]
    Memory at 09800000 (32-bit, non-prefetchable) [size=8M]
    Expansion ROM at 0a230000 [disabled] [size=64K]

0000:00:08.0 PCI bridge: Digital Equipment Corporation DECchip 21152 
(rev 03) (prog-if 00 [Normal decode])
    Flags: bus master, medium devsel, latency 255
    Bus: primary=00, secondary=01, subordinate=01, sec-latency=255
    I/O behind bridge: 00008000-00008fff
    Memory behind bridge: 0a000000-0a0fffff
    Prefetchable memory behind bridge: 000000000a100000-000000000a1fffff
    Capabilities: [dc] Power Management version 1

0000:01:00.0 SCSI storage controller: LSI Logic / Symbios Logic 53c875 
(rev 04)
    Flags: bus master, medium devsel, latency 255, IRQ 27
    I/O ports at 8000 [size=256]
    Memory at 0a002000 (32-bit, non-prefetchable) [size=256]
    Memory at 0a000000 (32-bit, non-prefetchable) [size=4K]
    Expansion ROM at 0a140000 [disabled] [size=64K]

0000:01:01.0 SCSI storage controller: LSI Logic / Symbios Logic 53c875 
(rev 04)
    Flags: bus master, medium devsel, latency 255, IRQ 26
    I/O ports at 8400 [size=256]
    Memory at 0a003000 (32-bit, non-prefetchable) [size=256]
    Memory at 0a001000 (32-bit, non-prefetchable) [size=4K]
    Expansion ROM at 0a150000 [disabled] [size=64K]

0000:01:02.0 Ethernet controller: Digital Equipment Corporation DECchip 
21140 [FasterNet] (rev 22)
    Subsystem: Digital Equipment Corporation Unknown device 500a
    Flags: bus master, medium devsel, latency 255, IRQ 25
    I/O ports at 8800 [size=128]
    Memory at 0a004000 (32-bit, non-prefetchable) [size=128]
    Expansion ROM at 0a100000 [disabled] [size=256K]

0001:02:07.0 Mass storage controller: Silicon Image, Inc. SiI 3124 PCI-X 
Serial ATA Controller (rev 02)
    Subsystem: Silicon Image, Inc. SiI 3124 PCI-X Serial ATA Controller
    Flags: bus master, stepping, 66MHz, medium devsel, latency 240, IRQ 47
    Memory at 209089000 (64-bit, non-prefetchable) [size=128]
    Memory at 209080000 (64-bit, non-prefetchable) [size=32K]
    I/O ports at 200008820 [size=16]
    Expansion ROM at 209000000 [disabled] [size=512K]
    Capabilities: [64] Power Management version 2
    Capabilities: [40] PCI-X non-bridge device
    Capabilities: [54] Message Signalled Interrupts: Mask- 64bit+ 
Queue=0/0 Enable-

0001:02:08.0 RAID bus controller: VIA Technologies, Inc. VT6421 IDE RAID 
Controller (rev 50)
    Subsystem: VIA Technologies, Inc. VT6421 IDE RAID Controller
    Flags: bus master, medium devsel, latency 240, IRQ 43
    I/O ports at 200008830 [size=16]
    I/O ports at 200008840 [size=16]
    I/O ports at 200008850 [size=16]
    I/O ports at 200008860 [size=16]
    I/O ports at 200008800 [size=32]
    I/O ports at 200008000 [size=256]
    Capabilities: [e0] Power Management version 2

0001:02:09.0 Ethernet controller: VIA Technologies, Inc. 
VT6120/VT6121/VT6122 Gigabit Ethernet Adapter (rev 01)
    Subsystem: ZyXEL Communication Corporation Unknown device 3302
    Flags: bus master, 66MHz, medium devsel, latency 248, IRQ 39
    I/O ports at 200008400 [size=256]
    Memory at 209088000 (32-bit, non-prefetchable) [size=256]
    Capabilities: [50] Power Management version 2

Re: Port Multiplier Patch 2.6.22.1 on Alpha

[Tom Evans]

I decided to put the Norco 4618 card into the first PCI slot of my DS20.

It and the PMP support seem to like that location much better - I'm 
successfully creating an array at the moment (with not much apparent 
slowdown to the system).

I was able to move the graphics card to another slot (which for a period 
in the past was also limited to the first PCI slot).

Maybe this will make sense to some folks out there - thanks!

...tom


Jeff Garzik wrote:
> Tom Evans wrote:
>> Have you heard of such and issue with the 3124-2/4276 combination?
>> Is anyone else trying this driver on an Alpha?
>
> Alpha should not be operationally much different from other little 
> endian 64-bit platforms.
>
> The PCI swizzle might be weird (what is your Alpha platform?), is the 
> only Alpha-specific thing that comes to mind.
>
>
>> I have similar such behavior before when using drivers that generate 
>> many unaligned accesses - I only have seen 2 places they occur in 
>> sata_sil24 and have fixed them myself, but that made no difference.
>
> We definitely want to fix all these you find.  Please post more info...
>
> Also, if you are highly motivated, I would love to see if other SATA 
> cards have similar problems on Alpha...
>
>     Jeff
>
>
>

Re: Port Multiplier Patch 2.6.22.1 on Alpha

[Tom Evans]

I decided to put the Norco 4618 card into the first PCI slot of my DS20.

It and the PMP support seem to like that location much better - I'm 
successfully creating an array at the moment.

The system still responds, but accessing currently running filesystems 
(another array and the local scsi boot disk) seems to "freeze" for 20-30 
seconds.

I was able to move the graphics card to another slot (which for a period 
in the past was also limited to the first PCI slot).

Maybe this will make sense to some folks out there - thanks!

...tom


Jeff Garzik wrote:
> Tom Evans wrote:
>> Have you heard of such and issue with the 3124-2/4276 combination?
>> Is anyone else trying this driver on an Alpha?
>
> Alpha should not be operationally much different from other little 
> endian 64-bit platforms.
>
> The PCI swizzle might be weird (what is your Alpha platform?), is the 
> only Alpha-specific thing that comes to mind.
>
>
>> I have similar such behavior before when using drivers that generate 
>> many unaligned accesses - I only have seen 2 places they occur in 
>> sata_sil24 and have fixed them myself, but that made no difference.
>
> We definitely want to fix all these you find.  Please post more info...
>
> Also, if you are highly motivated, I would love to see if other SATA 
> cards have similar problems on Alpha...
>
>     Jeff
>
>
>

Re: Port Multiplier Patch 2.6.22.1 on Alpha

[Tom Evans]

I decided to put the Norco 4618 card into the first PCI slot of my DS20.

It and the PMP support seem to like that location much better - I'm 
successfully creating an array at the moment.

The system still responds, but accessing currently running filesystems 
(another array and the local scsi boot disk) seems to "freeze" for 20-30 
seconds.

I was able to move the graphics card to another slot (which for a period 
in the past was also limited to the first PCI slot).

Maybe this will make sense to some folks out there - thanks!

...tom


Jeff Garzik wrote:
> Tom Evans wrote:
>> Have you heard of such and issue with the 3124-2/4276 combination?
>> Is anyone else trying this driver on an Alpha?
>
> Alpha should not be operationally much different from other little 
> endian 64-bit platforms.
>
> The PCI swizzle might be weird (what is your Alpha platform?), is the 
> only Alpha-specific thing that comes to mind.
>
>
>> I have similar such behavior before when using drivers that generate 
>> many unaligned accesses - I only have seen 2 places they occur in 
>> sata_sil24 and have fixed them myself, but that made no difference.
>
> We definitely want to fix all these you find.  Please post more info...
>
> Also, if you are highly motivated, I would love to see if other SATA 
> cards have similar problems on Alpha...
>
>     Jeff
>
>
>

Re: Port Multiplier Patch 2.6.22.1 on Alpha

[Tom Evans]

I decided to put the Norco 4618 card into the first PCI slot of my DS20.

It and the PMP support seem to like that location much better - I'm 
successfully creating an array at the moment.

The system still responds, but accessing currently running filesystems 
(another array and the local scsi boot disk) seems to "freeze" for 20-30 
seconds.

I was able to move the graphics card to another slot (which for a period 
in the past was also limited to the first PCI slot).

Maybe this will make sense to some folks out there - thanks!

...tom


Jeff Garzik wrote:
> Tom Evans wrote:
>> Have you heard of such and issue with the 3124-2/4276 combination?
>> Is anyone else trying this driver on an Alpha?
>
> Alpha should not be operationally much different from other little 
> endian 64-bit platforms.
>
> The PCI swizzle might be weird (what is your Alpha platform?), is the 
> only Alpha-specific thing that comes to mind.
>
>
>> I have similar such behavior before when using drivers that generate 
>> many unaligned accesses - I only have seen 2 places they occur in 
>> sata_sil24 and have fixed them myself, but that made no difference.
>
> We definitely want to fix all these you find.  Please post more info...
>
> Also, if you are highly motivated, I would love to see if other SATA 
> cards have similar problems on Alpha...
>
>     Jeff
>
>
>

Re: Port Multiplier Patch 2.6.22.1 on Alpha

[Tom Evans]

I decided to put the Norco 4618 card into the first PCI slot of my DS20.

It and the PMP support seem to like that location much better - I'm 
successfully creating an array at the moment.

The system still responds, but accessing currently running filesystems 
(another array and the local scsi boot disk) seems to "freeze" for 20-30 
seconds.

I was able to move the graphics card to another slot (which for a period 
in the past was also limited to the first PCI slot).

Maybe this will make sense to some folks out there - thanks!

...tom


Jeff Garzik wrote:
> Tom Evans wrote:
>> Have you heard of such and issue with the 3124-2/4276 combination?
>> Is anyone else trying this driver on an Alpha?
>
> Alpha should not be operationally much different from other little 
> endian 64-bit platforms.
>
> The PCI swizzle might be weird (what is your Alpha platform?), is the 
> only Alpha-specific thing that comes to mind.
>
>
>> I have similar such behavior before when using drivers that generate 
>> many unaligned accesses - I only have seen 2 places they occur in 
>> sata_sil24 and have fixed them myself, but that made no difference.
>
> We definitely want to fix all these you find.  Please post more info...
>
> Also, if you are highly motivated, I would love to see if other SATA 
> cards have similar problems on Alpha...
>
>     Jeff
>
>
>

Re: Port Multiplier Patch 2.6.22.1 on Alpha

[Tom Evans]

Sorry about the spam - said system is my mail server and the mail 
program, although I though had timed-out the sends still got the 
messages thru.

...tom

Re: Port Multiplier Patch 2.6.22.1 on Alpha

[Tejun Heo]

Tom Evans wrote:
> 
> I decided to put the Norco 4618 card into the first PCI slot of my DS20.
> 
> It and the PMP support seem to like that location much better - I'm
> successfully creating an array at the moment.
> 
> The system still responds, but accessing currently running filesystems
> (another array and the local scsi boot disk) seems to "freeze" for 20-30
> seconds.

Does kernel complain anything during the freeze?

> I was able to move the graphics card to another slot (which for a period
> in the past was also limited to the first PCI slot).
> 
> Maybe this will make sense to some folks out there - thanks!

To me, not much yet.  :-(

-- 
tejun

Re: Port Multiplier Patch 2.6.22.1 on Alpha

[Tejun Heo]

Tom Evans wrote:
> I do not see any console or syslog messages at the time - perhaps I do
> not have a debug level set appropriately?

Executing dmesg after the event should give you the messages if the
kernel has spoken anything.

> Also, as an aside, I noticed that the device scan on the remote array
> shows this device:
> 
> Sep  8 00:15:12 chronictown kernel: [4194044.507921] ata4.05: ATA-6:
> Config  Disk, PLS12052, max UDMA/133
> Sep  8 00:15:12 chronictown kernel: [4194044.507921] ata4.05: 640
> sectors, multi 1: LBA
> Sep  8 00:15:12 chronictown kernel: [4194044.507921] ata4.05: device is
> on DMA blacklist, disabling DMA
> Sep  8 00:15:12 chronictown kernel: [4194044.507921] ata4.05: configured
> for PIO4
> 
> 
> I couldn't find any reference - is this firmware for the PMP or
> something like that?

That's the pseudo device for configuration.  It can be safely ignored
unless it causes problems.

Thanks.

-- 
tejun