Messages in this thread | | | From | "Rafael J. Wysocki" <> | Subject | Re: Bugs in MMC [was: [Bug 10030] Suspend doesn't work when SD card is inserted] | Date | Thu, 6 Mar 2008 22:31:13 +0100 |
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On Thursday, 6 of March 2008, Zdenek Kabelac wrote: > 2008/3/6, Alan Stern <stern@rowland.harvard.edu>: > > On Thu, 6 Mar 2008, Pavel Machek wrote: > > > > > On Tue 2008-03-04 16:00:51, Alan Stern wrote: > > > > On Tue, 4 Mar 2008, David Brownell wrote: > > > > > > > > > > What's wrong with a superfluous probe at resume time, besides the waste > > > > > > of a few milliseconds? > > > > > > > > > > I'm more concerned with the undesirable removal of devices at suspend > > > > > time ... ones with mounted filesystems etc. > > > > > > > > On that we can agree. The removal is done if the host doesn't define a > > > > resume method. There doesn't seem to be any point to that, given that > > > > the probing during resume will determine whether a card has in fact > > > > been removed. > > > > > > Hmm, if the driver is sleeping too deeply, user might have removed the > > > card and put in different one, without driver noticing. That would be > > > _bad_. > > > > > > Ironically, the very same problem now exists with the USB mass-storage > > driver. I don't see any way for the driver itself to solve it, > > especially during a hibernation (which can be a _very_ deep sleep). > > > > One thing that could be done is for filesystems to verify, after a > > system sleep, that their superblocks haven't changed. There could > > still be issues with non-mounted partitions, if they have live entries > > in the block cache, but it would be an improvement. > > > > Do you know the right people to mention this to? Anybody in filesystem > > development interested in suspend/hibernation issues?
I don't really think so (but I may be wrong ...)
> IMHO the way would be to try to unmount fs if it's possible - if not - > user should be notified on suspend/hibernation that he must preserve > media in its place after resume and it should be checked and user > should be notified if different devices/fs were find...
This is a very long standing issue which IMO can only be solved by making filesystems suspend-aware.
Thanks, Rafael
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