Messages in this thread | | | From | Maxim <> | Subject | Re: USB: on suspend to ram/disk all usb devices are replugged | Date | Wed, 28 Mar 2007 01:29:10 +0200 |
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On Tuesday 27 March 2007 20:05:24 Pete Zaitcev wrote: > On Tue, 27 Mar 2007 13:15:14 -0400 (EDT), Alan Stern <stern@rowland.harvard.edu> wrote: > > > > Suspend to disk still causes "virtual replugging" and I think that controller is reset and will unplug/replug devices anyway > > > Resolving this problem is very difficult. Maybe it possible to check on unplugging event that this caused by suspend if the same device is > > > replugged then don't remove/reinstall driver, but this is very difficult to implement properly, > > > Maybe just refuse to suspend if some valuable device is connected (sorry if it is done this way already) > > > > Long ago I posted a patch that would take care of all this. Not just for > > UHCI, but for any USB controller. Maybe I should dig it out, update it, > > and submit it. > > Alan, BTW, look at this please: > > https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=233697 > > > From David Zeuthen > > > If I suspend my box, then on the resume path I see all my USB devices being > > removed and then added back. This is a problem with storage devices connected > > via USB. > ..... > > The kernel not send an "remove" event if it's going to send an "add" right > > after. Instead it should enumerate the bus on resume and only send the events > > that represents how to get from the previous device tree to the current one. > > > From Pete Zaitcev > > > What does happen if a user suspends, unplugs a USB key, modifies its contents, > > plugs it back, and resumes? In such a case, there would be no change between > > the state of USB bus between the before-suspend state and after-resume state. > > > From David Zeuthen > > > In that case the user would see data corruption - just as if he mounts a piece > > of removable media in a USB card reader; yanks out the card and modifies it > > elsewhere, and then puts it back in. > > > I my opinion we can't really defend ourselves against such users... We can of > > course add checks in the file system drivers in the resume hooks to validate the > > super block and mount read-only if something change. > > The GNOME hath spoken? > > -- Pete >
Hi, I also thought about that,
I think that the best solution is still to hide connect/disconnect of usb devices from userspace (now it also causes corruption) But to refuse suspend with any usb mass storage device connected with mounted systems (and add a module param override for users who know what they are doing)
What do you think ?
Regards, Maxim Levitsky - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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