RE: [PATCH] power/hibernate: Make passing hibernate offsets more friendly

[Mario.Limonciello]

> -----Original Message-----
> From: rjwysocki@xxxxxxxxx [mailto:rjwysocki@xxxxxxxxx] On Behalf Of Rafael J.
> Wysocki
> Sent: Monday, March 26, 2018 4:38 AM
> To: Limonciello, Mario <Mario_Limonciello@xxxxxxxx>
> Cc: Rafael J. Wysocki <rjw@xxxxxxxxxxxxx>; ACPI Devel Maling List <linux-
> acpi@xxxxxxxxxxxxxxx>; Linux Kernel Mailing List <linux-kernel@xxxxxxxxxxxxxxx>
> Subject: Re: [PATCH] power/hibernate: Make passing hibernate offsets more friendly
> 
> On Mon, Mar 26, 2018 at 9:17 AM,  <Mario.Limonciello@xxxxxxxx> wrote:
> >> -----Original Message-----
> >> From: Rafael J. Wysocki [mailto:rjw@xxxxxxxxxxxxx]
> >> Sent: Monday, March 19, 2018 5:11 AM
> >> To: Limonciello, Mario <Mario_Limonciello@xxxxxxxx>
> >> Cc: linux-acpi@xxxxxxxxxxxxxxx; LKML <linux-kernel@xxxxxxxxxxxxxxx>
> >> Subject: Re: [PATCH] power/hibernate: Make passing hibernate offsets more
> friendly
> >>
> >> On Tuesday, March 6, 2018 11:53:40 AM CET Mario Limonciello wrote:
> >> > Currently the only way to specify a hibernate offset for a
> >> > swap file is on the kernel command line.
> >> >
> >> > Add a new /sys/power/disk_offset that lets userspace
> >> > specify the offset and disk to use when initiating a hibernate
> >> > cycle.
> >> >
> >> > Also split up the parsing routine to re-use the same code
> >> > for the /sys/power/resume and /sys/power/disk_offset parsing.
> >> >
> >> > Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxxx>
> >>
> >> Well, IMO /sys/power/resume and /sys/power/disk_offset would be confusingly
> >> similar after this patch.
> >
> > Yeah they do function pretty similarly.
> >
> >>
> >> I wonder if adding a resume_offset sysfs attr to simply allow the value of
> >> resume offset alone to be passed to the kernel at run time (in addition to
> >> the command line) would work?
> >>
> >> Thanks!
> >
> > I guess what's your expected flow for how the disk gets selected though?  Should
> > the kernel be "guessing" which disk to use?
> >
> > Or should userspace be setting offset via /sys/power/resume_offset followed by
> > disk in /sys/power/resume (which will show an error in syslog about no partition
> > found)
> >
> > If the latter,
> 
> Yes, the latter.
> 
> > then I'd like to also modify the behavior to downgrade that missing
> > hibernate partition to debug instead too.
> 
> That's OK.

OK thanks, I'll adjust per your recommendations.