Linda Walsh writes: > Robert Hancock wrote: > > Linda Walsh wrote: > >> Alan Cox wrote: > >>>> rate began falling; at 128k block-reads-at-a-time or larger, it > >>>> drops below > >>>> 20MB/s (only on buffered SATA). > >>> Try disabling NCQ - see if you've got a drive with the 'NCQ = no > >>> readahead' flaw. > > http://linux-ata.org/faq.html#ncq > --- > When drive initializes, dmesg says it has NCQ (depth 0/32) > Reading the queue_depth under /sys, shows a queuedepth of "1". > > But more importantly -- I notice a chronic error message associate > with this drive that may be causing some or all of the problem: > --- > Jan 2 20:06:10 Ishtar kernel: ata1.00: exception Emask 0x0 SAct 0x0 > SErr 0x0 action 0x2 > Jan 2 20:06:10 Ishtar kernel: ata1.00: port_status 0x20080000 > Jan 2 20:06:10 Ishtar kernel: ata1.00: cmd > c8/00:10:30:06:03/00:00:00:00:00/e0 tag 0 cdb 0x0 data 8192 in > Jan 2 20:06:10 Ishtar kernel: res > 50/00:00:3f:06:03/00:00:00:00:00/e0 Emask 0x2 (HSM violation) > Jan 2 20:06:13 Ishtar kernel: ata1: limiting SATA link speed to 1.5 Gbps > Jan 2 20:06:13 Ishtar kernel: ata1.00: exception Emask 0x0 SAct 0x0 > SErr 0x0 action 0x6 > Jan 2 20:06:13 Ishtar kernel: ata1.00: port_status 0x20080000 > Jan 2 20:06:13 Ishtar kernel: ata1.00: cmd > c8/00:10:00:8b:04/00:00:00:00:00/e0 tag 0 cdb 0x0 data 8192 in > Jan 2 20:06:13 Ishtar kernel: res > 50/00:00:0f:8b:04/00:00:00:00:00/e0 Emask 0x2 (HSM violation) > Jan 2 20:06:14 Ishtar kernel: ata1: exception Emask 0x10 SAct 0x0 SErr > 0x0 action 0x3 > Jan 2 20:06:14 Ishtar kernel: ata1: hotplug_status 0x80 > Jan 2 20:06:15 Ishtar kernel: ata1: exception Emask 0x10 SAct 0x0 SErr > 0x0 action 0x3 > Jan 2 20:06:15 Ishtar kernel: ata1: hotplug_status 0x80 > --- > What da heck? Looks like the Promise ASIC SG bug. Apply <http://user.it.uu.se/~mikpe/linux/patches/sata_promise/patch-sata_promise-1-asic-sg-bug-fix-v3-2.6.23> and let us know if things improve. /Mikael - To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
