USB Flash reader under RELENG_6: force GEOM rescan

[Oliver Fromme]

Dmitry Morozovsky <marck at rinet.ru> wrote:
 > I have USB multi-LUN flash reader which is identified under RELENG_6 as
 > umass0: GENERIC USB Storage Device, rev 2.00/1.8a, addr 2
 > da0 at umass-sim0 bus 0 target 0 lun 0
 > da0: <GENERIC USB Storage-CFC I19B> Removable Direct Access SCSI-0 device 
 > da0: 40.000MB/s transfers
 > da0: Attempt to query device size failed: NOT READY, Medium not present
 > [...]
 > when I insert flash into one of slots, I need to rescan da* providers, as 
 > usually there is slice1 which should be mounted. 

The problem is that devfs isn't "triggered", therefore it
doesn't notice that a new device appeared, so no new nodes
are created.

 > How can I achieve this? camcomtrol rescan does not help, and for now I've found 
 > only *very* ugly workaround like
 > 
 > dd if=/dev/da0 of=/dev/da0 count=1 
 > 
 > which results in error, but actually create GEOMs

The following should work as well, without giving an error:

dd if=/dev/null of=/dev/da0 count=0

It opens the device for writing (without actually writing
anything) and immediately closes it again, which causes
devfs to be "triggered".

I don't think there's currently a real fix for the problem,
I'm afraid.

Best regards
   Oliver

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Oliver Fromme,  secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing
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