timeout/hardreset a device manually?

[Tomasz Chmielewski <mangoo@wpkg.org>]

Is it possible to "timeout" and/or "hardreset" a device "manually"?

I'm trying to debug a weird system freeze, I think being able to make 
the device "timeout" and eventually "hardreset" would be helpful in 
diagnosing this problem.

In other words, I'd like to be able to "manually" achieve this:

ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen
ata1.00: cmd 35/00:08:3f:7c:93/00:00:2e:00:00/e0 tag 0 dma 4096 out
          res 40/00:01:00:4f:c2/00:00:00:00:00/00 Emask 0x4 (timeout)
ata1.00: status: { DRDY }
ata1: hard resetting link
ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 310)
ata1.00: max_sectors limited to 256 for NCQ
ata1.00: max_sectors limited to 256 for NCQ
ata1.00: configured for UDMA/33
ata1: EH complete
sd 1:0:0:0: [sdb] 781422768 512-byte hardware sectors (400088 MB)
sd 1:0:0:0: [sdb] Write Protect is off
sd 1:0:0:0: [sdb] Mode Sense: 00 3a 00 00
sd 1:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't 
support DPO or FUA


-- 
Tomasz Chmielewski
http://wpkg.org