alistair23-linux/Documentation/ABI/testing/sysfs-driver-samsung-laptop
Julijonas Kikutis b0dcaf4fbb samsung-laptop: enable better lid handling
Some Samsung laptops with SABI3 delay the sleep for 10 seconds after
the lid is closed and do not wake up from sleep after the lid is opened.
A SABI command is needed to enable the better behavior.

Command = 0x6e, d0 = 0x81 enables this behavior. Returns d0 = 0x01.
Command = 0x6e, d0 = 0x80 disables this behavior. Returns d0 = 0x00.

Command = 0x6d and any d0 queries the state. This returns:
d0 = 0x00000*01, d1 = 0x00, d2 = 0x00, d3 = 0x0* when it is enabled.
d0 = 0x00000*00, d1 = 0x00, d2 = 0x00, d3 = 0x0* when it is disabled.
Where * is 0 - laptop has never slept or hibernated after switch on,
           1 - laptop has hibernated just before,
           2 - laptop has slept just before.

Patch addresses bug https://bugzilla.kernel.org/show_bug.cgi?id=75901 .
It adds a sysfs attribute lid_handling with a description and also an
addition to the quirks structure to enable the mode by default.

A user with another laptop in the bug report says that "power button has
to be pressed twice to wake the machine" when he or she enabled the mode
manually using the SABI command. Therefore, it is enabled by default
only for the single laptop that I have tested.

Signed-off-by: Julijonas Kikutis <julijonas.kikutis@gmail.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
2015-02-06 18:33:55 -08:00

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What: /sys/devices/platform/samsung/performance_level
Date: January 1, 2010
KernelVersion: 2.6.33
Contact: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Description: Some Samsung laptops have different "performance levels"
that are can be modified by a function key, and by this
sysfs file. These values don't always make a whole lot
of sense, but some users like to modify them to keep
their fans quiet at all costs. Reading from this file
will show the current performance level. Writing to the
file can change this value.
Valid options:
"silent"
"normal"
"overclock"
Note that not all laptops support all of these options.
Specifically, not all support the "overclock" option,
and it's still unknown if this value even changes
anything, other than making the user feel a bit better.
What: /sys/devices/platform/samsung/battery_life_extender
Date: December 1, 2011
KernelVersion: 3.3
Contact: Corentin Chary <corentin.chary@gmail.com>
Description: Max battery charge level can be modified, battery cycle
life can be extended by reducing the max battery charge
level.
0 means normal battery mode (100% charge)
1 means battery life extender mode (80% charge)
What: /sys/devices/platform/samsung/usb_charge
Date: December 1, 2011
KernelVersion: 3.3
Contact: Corentin Chary <corentin.chary@gmail.com>
Description: Use your USB ports to charge devices, even
when your laptop is powered off.
1 means enabled, 0 means disabled.
What: /sys/devices/platform/samsung/lid_handling
Date: December 11, 2014
KernelVersion: 3.19
Contact: Julijonas Kikutis <julijonas.kikutis@gmail.com>
Description: Some Samsung laptops handle lid closing quicker and
only handle lid opening with this mode enabled.
1 means enabled, 0 means disabled.