Hi, On Tuesday, 6 of September 2005 16:50, Alan Stern wrote: > On Mon, 5 Sep 2005, David Brownell wrote: > > > > With the USB device, things are more interesting. If you unplug the > > > device (even while it's not in use), Windows warns you not to do this > > > without first getting permission by using the "Eject Removable Devices" > > > button. If you try to press that button while a program has a file open > > > on the device, Windows says that you can't remove the device right now and > > > advises you to try again later. > > > > So it's inconsistent in behavior, since this isn't how it handles > > the same thing during resume-from-hibernate ... > > Obviously because Windows isn't aware of anything that happens during > hibernate while the power is turned off. How could it possibly warn you > about unplugging a device when it doesn't know whether you unplugged the > device or not? > > If you describe the behavior as "Windows warns you whenever it learns that > you ejected removable media without permission", then Windows _is_ > consistent. > > > > However... I put the laptop into Hibernate mode. To be absolutely sure > > > this was a true snapshot-poweroff-resume cycle, I also unplugged the power > > > cord and removed the battery. Then I removed and replaced the USB device > > > and restarted the laptop. Everything worked smoothly; the file remained > > > open and the program was able to continue reading it, well past the point > > > where the I/O buffers needed to be refilled. > > > > So basically there's a special case somewhere to treat _this_ disconnect > > differently than other ones. > > Yes, there must be. > > > How does real suspend behave (like STR)? How does it handle cases where you > > plug in a different instance of the same device ... example, different CF > > card in a CF reader? Or when you move the device to another port? And > > does XP behave identically? > > I'll try doing some of those experiments when I have a chance. > > > > If Windows ME can do this, Linux should be able to do it too. > > > > That argument can be stretched too far! Though from time to time I have > > indeed wished for something more like a BSOD. An oops hidden in a logfile > > that never gets flushed to disk, with an X desktop, gives no clues ... :) > > > > Linux certainly _could_ try to emulate up all the fault handling of some > > version of Windows. But whether it _should_ is a different story. > > I say this is a case where we should try, at least to some extent; users > will feel that "Powerdown-swsusp automatically removes all hot-pluggable > devices" is too Draconian. > > What do other people on the PM list think? I think it is analogous to leaving a mounted CD in the drive and suspending. If you resume the box without ejecting the CD, it remains mounted and all is fine (I actually tested this). I don't know what happens if you remove the CD from the drive while suspended (from the Linux' point of view), but this is a different kettle of fish. Anyway, IMO, the behavior should be consistent across all devices or users will get confused. Greetings, Rafael -- - Would you tell me, please, which way I ought to go from here? - That depends a good deal on where you want to get to. -- Lewis Carroll "Alice's Adventures in Wonderland"
