Messages in this thread | | | Date | Tue, 26 Jul 2011 08:33:17 -0500 | From | Seth Forshee <> | Subject | Re: [PATCH] usb_storage: make usb-stor-scan task non-freezable |
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On Sat, Jul 23, 2011 at 09:56:15PM -0400, Alan Stern wrote: > On Sat, 23 Jul 2011, Seth Forshee wrote: > > > After experimenting with this device more I came to the conclusion that > > the normal behavior with this machine is for the card reader to be > > disconnected from the USB bus unless there's a card in the slot. During > > a normal boot with an empty card slot the card reader never shows up on > > the bus. > > Weird. Then the reader would never be usable. Unless it connects > itself to the bus when a card is inserted?
Yes, the reader is connected to the bus when a card is inserted. Remove the card and it disappears again.
> > The only solution I've come up with is to leave usb-stor-scan freezable > > without allowing it to actually freeze. We can request a fake signal be > > sent when freezing and use interruptible sleep to abort the wait early > > and finish up the thread's processing. This is implemented in the patch > > below. Does this approach look reasonable? It's rather subtle, but it > > does seem to work. I done numerous S4 cycles with and without a card > > inserted and didn't get any failures. > > This runs the risk of failing to suspend if scanning takes too long.
It may increase the exposure to that risk, but really the risk is already there.
> On the other hand, many systems nowadays use async scanning anyway. > And that combination of events isn't too likely to happen, whereas > you're facing a real problem right now. So I guess this is okay.
Great, thanks.
Will the patch get picked up from my previous email, or do I need to resend it?
Thanks, Seth
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