Re: Regression in suspend to ram in 2.6.31-rc kernels

From: Pavel Machek
Date: Mon Sep 07 2009 - 08:52:55 EST


> >>> Note that when you rever this patch on a current kernel you do actually
> >>> get different behvaviour than when going back to before this commit.
> >>>
> >>> In 2.6.30 we called ->write_super in the various sync functions and
> >>> then ->sync_fs, in 2.6.31-rc8 you would not call any syncing at all
> >>> anymore. ?I think this patch might just be a symptom for a situation
> >>> where the suspend code causes a sync and the mmc driver can't handle
> >>> it anymore.
> >
> > So - here is the console trace from suspend when I've added
> > dump_stack() to the fat_sync_fs() (and also added debug prints
> > around each call in this function -so its obvious the function is
> > actually left - but then it freezes later somewhere.)
> >
> > It's interesting that 3 calls to sync happens.
> It seems
> 1) sync() (probabry "sync" command)
> 2) sync as part of suspend sequence
> 3) sync_filesystem() by mmc remove event
> I guess the root-cause of the problem would be 3). However, it would not
> be easy to fix, at least, we would need to think about what we want to
> do for it. So, to workaround it for now, I've made this patch.

MMC driver trying to synchronize filesystems looks like ugly layering
violation to me. Why are we doing that?

(cesky, pictures)
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at