Messages in this thread | | | Date | Thu, 15 Jan 2009 10:13:37 -0500 (EST) | From | Alan Stern <> | Subject | Re: A really interesting mass-storage BUG introduced after 2.6.18 |
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On Thu, 15 Jan 2009, Iwo Mergler wrote:
> > > > This shows the computer sending a TEST UNIT READY command to the drive, > > and the drive reporting Unit Attention: Media not present. So of > > course Linux believes there is no media loaded in the drive and doesn't > > try to read the partition table or anything else. > > > > Presumably if the drive is plugged in during bootup then the BIOS does > > something to make this error status go away. It's hard to guess what > > that would be, however. > > > > It could be a matter of timing. Some badly designed USB devices have a > dead time between power-up and being ready, but show up on the bus as > if they where. The "Media not present" thing could be a symptom of this.
Good point.
> To verify it, try inserting the device slowly. The power contacts in > the USB connector are longer than the data contacts and the device gets > more time to boot.
Another timing-sensitive values you can set is the delay_use module parameter for usb-storage. It defaults to 5 seconds but perhaps you need a longer delay.
Alan Stern
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