Messages in this thread |  | | Subject | Re: Doubts on IO requests in USB subsystem | | From | Oliver Neukum <> | | Date | Mon, 16 Sep 2013 13:06:39 +0200 |
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On Mon, 2013-09-16 at 10:33 +0000, Morales, Alejandra wrote: > 2013/9/9 Oliver Neukum <oliver@neukum.org> > > > > Your prime suspect is the detection of medium change which was > > moved into the kernel in 3.2 or so. It can be disabled by sysfs. > > Generally the notion that a certain task originates a read or write > > on a block device is iffy. Read-ahead and shared data structures > > make it impossible to accurately tell. > > > > USB storage devices are notorious for setting the removable bit > > even if they have no removable medium. > > > > Thanks for the answer Oliver. Unfortunately it doesn't seem to be the > medium change detection what is causing these requests, since the > removable bit is disabled and the polling period is set to -1:
Interesting. Then you have no choice. Make a usbmon trace and look at the SCSI commands going to the device.
HTH Oliver
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