[lkml]   [2011]   [Jul]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: [PATCH] usb_storage: make usb-stor-scan task non-freezable
    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?


     \ /
      Last update: 2011-07-26 15:35    [W:0.024 / U:11.788 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site