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From: Andrew Marshall <andrewmarshall@orange.net>
To: linux-hotplug@vger.kernel.org
Subject: USB card reader media detection
Date: Fri, 01 Apr 2005 11:40:34 +0000	[thread overview]
Message-ID: <000701c536af$9e5e8b20$f601a8c0@SenatorPalmer> (raw)

Hi all,

I would very much appreciate any assistance anyone can offer on the
following:

I am currently running version 2.4.22 of the Kernel and am writing an
application that needs to cope with the removal of card media form a USB
flash card reader.

Hotplug informs me when the card reader itself is added with my intention
being to scan for partition entries at the newly created dev/scsi entry

	e.g	/dev/scsi/host0/bus0/target0/lun0/part1

and mount any partitions detected.

This works fine -- but I also need to detect when a memory card has been
removed.

I have found that the block device file (part1) corresponding to my flash
card's partition is appropriately updated (i.e removed from
/dev/scsi/host0/bus0/target0/lun0/ when the test card is removed) -- but
only if the partition is *not* currently mounted!

I found that once I have mounted the partition, the devfs 'part1' block
device perpetually remains -- even when the card is removed, thus making
removal detection a tad tricky.

OK, it seems to be possible to unmount the partition, poll the
/dev/scsi/host0/bus0/target0/lun0 entry and then remount once the poller has
determined that the partition is still present -- but this takes time... And
also seems a little extreme (if not ridiculous)...

Does anyone have any ideas on a fix or alternative way to determine removal
of a flash card from a connected flash card reader.

Any suggestions on this problem would be greatly appreciated. Many thanks!


Andrew Marshall





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             reply	other threads:[~2005-04-01 11:40 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-04-01 11:40 Andrew Marshall [this message]
2005-04-01 14:40 ` USB card reader media detection Kay Sievers
2005-04-05 17:51 ` Greg KH
2005-04-06 11:06 ` Andrew Marshall

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