-test7: /sys/power/disk not reading right data?
Hi!
I'm seeing this on -test7 (tainted:pavel, but I did not touch this area).
Pavel
root@amd:~# echo -n platform > /sys/power/disk root@amd:~# dmesg | tail -1 PM: suspend-to-disk mode set to 'platform' root@amd:~# cat /sys/power/disk firmware root@amd:~#
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When do you have a heart between your knees? [Johanka's followup: and *two* hearts?]
Hi!
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I'm seeing this on -test7 (tainted:pavel, but I did not touch this area).
Reproduced on -test7-bk, vanilla.
I really do not think that 2 separate files (disk, state) are good idea. It bitten me, again. I did echo -n platform > disk, echo -n disk
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state. Unfortunately kernel somehow decided that platform suspend is
not supported, but honoured second request. Result is crash, of course. This error would be avoided if I said echo -n swsusp > state (or similar), because unrecognized/unsupported request would be simply not done.
What advantages does disk/ state separation have? I believe that echo swsusp > state (or echo s4bios > state or echo disk-firmware > state) is the right interface, and that we want to do echo "s4bios" > on_battery_low or similar interface. (echo "mem" > on_battery_low makes sense, too, toshiba notebooks do that for example).
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root@amd:~# echo -n platform > /sys/power/disk root@amd:~# dmesg | tail -1 PM: suspend-to-disk mode set to 'platform' root@amd:~# cat /sys/power/disk firmware root@amd:~#
Pavel
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When do you have a heart between your knees? [Johanka's followup: and *two* hearts?]
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I'm seeing this on -test7 (tainted:pavel, but I did not touch this area).
Reproduced on -test7-bk, vanilla.
It's a known bug. If your system supports both S4 and S4bios, only the latter may be selected.
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What advantages does disk/ state separation have? I believe that echo swsusp > state (or echo s4bios > state or echo disk-firmware > state) is the right interface, and that we want to do echo "s4bios" >
on_battery_lowor similar interface. (echo "mem" >on_battery_lowmakes sense, too, toshiba notebooks do that for example).
The string 's4bios' only makes sense on systems that support it, while 'disk' is concise and obvious, regardless on how your platform implements it. I don't want to have options that are only relevant on a subset of the systems out there.
Pat
Hi!
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What advantages does disk/ state separation have? I believe that echo swsusp > state (or echo s4bios > state or echo disk-firmware > state) is the right interface, and that we want to do echo "s4bios" >
on_battery_lowor similar interface. (echo "mem" >on_battery_lowmakes sense, too, toshiba notebooks do that for example).The string 's4bios' only makes sense on systems that support it, while 'disk' is concise and obvious, regardless on how your platform implements it. I don't want to have options that are only relevant on a subset of the systems out there.
So call it disk-firmware.
The two-files interface is accident waiting for happen. (And accident that already happened, it crashed my machine at least twice).
Assume your user has 'echo platform > /sys/power/disk', and has suspend partition configured for BIOS.
He's used to suspending by echo disk > /sys/power/state. One day, for whatever reason (new kernel does not recognize s4bios?) platform suspend is unavailable. echo > /sys/power/disk is going to fail, but user is very unlikely to notice that. He is also very unlikely to cat /sys/power/disk before doing suspend. He does 'echo disk > /sys/power/disk', machine does swsusp (ouch). He can still save his data by adding resume=... parameter on next boot, but I guess it is unlikely to happen.
This looks very much like "trap for user" to me, and that trap already got me twice (s4bios does not really work here now, and I was trying to test pmdisk. It took me two fsck-s before I found out whats happening).
If you want to have concise and obvious interface, do echo 'disk-platform' vs. 'disk-firmware', or whatever, but please do not use two files.
Pavel
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When do you have a heart between your knees? [Johanka's followup: and *two* hearts?]