Re: [SoftwareSuspend-devel] 2.6 Suspend PM issues

[Pavel Machek <pavel@ucw.cz>]

Hi!

> > > > > By what was discussed wrt ALSA issue I gather that you still resume
> > > > > _all_ drivers after doing the atomic copy?
> > > > >
> > > > > As explained earlier this year, if this is the case, it is firstly
> > > > > unacceptable as it will result in loss of data in many applications and
> > > > > secondly very clumsy.
> > > > >
> > > > > Example With 2.4 OK, with 2.6 It would fail:
> > > > > A datalogger connected to a seral port of a notebook in the field. Data
> > > > > transfer in progress which can be put on hold bo lowering RTS (HW
> > > > > handshake) but _cannot_ be restarted. Battery low, must suspend to
> > > > > change battery, upon resume transfer can continue.
> > > > >
> > > > > Will this be taken care of?
> > >
> > > Driver will get enough info in its resume routine ("hey, it is resume,
> > > but it is only resume after atomic copy"), so it can ignore the resume
> > > if it really needs to.
> > 
> > Each driver has to make the decision when to ignore resume? that would add a 
> > lot of bloat as well as lots of work to implement and test the changes for 
> > 100s of drivers...
> 
> No, only those drivers where extra resume does some damage. So far I
> know about one, and that's your data logging device.

...which will not work anyway, swsusp1 or swsusp2. Have you actually
tried it?

During boot, BIOS is probably going to play with RTS anyway. So no
matter what you do during suspend, you are probably going to screw it
up anyway on the boot just before resume.

So there are currently 0 examples where extra resume hurts.
								Pavel
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