
30 Jul
2012
30 Jul
'12
9:18 p.m.
While tuning ext2load, we found that usb_test_unit_ready was being called every block read. We compared the usb block storage to the scsi block storage cmd_scsi.c, and found that the scsi device was only calling its scsi_setup_test_unit_ready() during scsi_can. It appears that usb_test_unit_ready() really only needs to be called once during usb_stor_scan(), via usb_stor_get_info(). Is there a particular reason usb_test_unit_ready is called for every block read, or do you think its ok to only call during usb_stor_scan()? We're finding this speeds up ext2load quite a bit.
Regards, Jim
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*James H Shimer*
Motorola Mobility T3-12-HH72
900 Chelmsford Street
Lowell MA 08151
978-614-3550