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    SubjectRe: [GIT PATCH] USB autosuspend fixes for 2.6.23-rc6
    On Thu, Sep 13, 2007 at 06:33:21AM -0700, Greg KH wrote:
    > It turns out that USB devices suck when it comes to powermanagement
    > issues :(
    > A number of patches have been submitted near the end of this kernel
    > release cycle that add new device ids to the quirk table in the kernel
    > to disable autosuspend for specific devices. However, a number of
    > developers are very worried that even with the testing that has been
    > done, once 2.6.23 is released, we are going to get a whole raft of angry
    > users when their devices break in nasty ways.
    > As an example, it seems that almost 2/3 of all USB printers just can not
    > handle autosuspend. And there's a _lot_ of USB printers out there...
    > When researching how other operating systems handle this, it was found
    > out that they use a whitelist of devices that are able to properly
    > suspend. So, in the future, that is how we are going to handle this.
    > These two patches address the need today to have users machines still
    > work, even if they might draw more power than they possibly could (which
    > is not any more than they did in 2.6.22.)
    > These patches do two things:
    > - disable USB autosuspend on all devices except for USB hubs. This
    > can be easily overridden by userspace to turn on autosuspend for
    > devices that a user wants to. HAL will use a whitelist in the
    > future for these types of devices.

    Not related to the patch for 2.6.23, but I have a gut feeling that
    something might be done the wrong way later:

    If I understand you correctly, you are saying that I will have to
    install HAL for getting a whitelist for in-kernel functionality?

    It is a good thing if userspace can add currently missing devices to
    whitelists, but the whitelist itself should be in the kernel.

    > thanks,
    > greg k-h



    "Is there not promise of rain?" Ling Tan asked suddenly out
    of the darkness. There had been need of rain for many days.
    "Only a promise," Lao Er said.
    Pearl S. Buck - Dragon Seed

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