Fico feliz em ter ajudado. Marque o tópico como resolvido, isso ajudará outras pessoas com o mesmo problema.
Quanto a explicação, creio que é um tanto técnico... veja isso:
acpi_osi= [HW,ACPI] Modify list of supported OS interface strings
acpi_osi="string1" # add string1
acpi_osi="!string2" # remove string2
acpi_osi=!* # remove all strings
acpi_osi=! # disable all built-in OS vendor
strings
acpi_osi= # disable all strings
'acpi_osi=!' can be used in combination with single or
multiple 'acpi_osi="string1"' to support specific OS
vendor string(s). Note that such command can only
affect the default state of the OS vendor strings, thus
it cannot affect the default state of the feature group
strings and the current state of the OS vendor strings,
specifying it multiple times through kernel command line
is meaningless. This command is useful when one do not
care about the state of the feature group strings which
should be controlled by the OSPM.
Examples:
1. 'acpi_osi=! acpi_osi="Windows 2000"' is equivalent
to 'acpi_osi="Windows 2000" acpi_osi=!', they all
can make '_OSI("Windows 2000")' TRUE.
'acpi_osi=' cannot be used in combination with other
'acpi_osi=' command lines, the _OSI method will not
exist in the ACPI namespace. NOTE that such command can
only affect the OSI support state, thus specifying it
multiple times through kernel command line is also
meaningless.
Examples:
1. 'acpiosi=' can make 'CondRefOf(_OSI, Local1)'
FALSE.
'acpi_osi=!' can be used in combination with single or
multiple 'acpi_osi="string1"' to support specific
string(s). Note that such command can affect the
current state of both the OS vendor strings and the
feature group strings, thus specifying it multiple times
through kernel command line is meaningful. But it may
still not able to affect the final state of a string if
there are quirks related to this string. This command
is useful when one want to control the state of the
feature group strings to debug BIOS issues related to
the OSPM features.
Examples:
1. 'acpi_osi="Module Device" acpi_osi=!' can make
'OSI("Module Device")' FALSE.
2. 'acpiosi=! acpi_osi="Module Device"' can make
'OSI("Module Device")' TRUE.
3. 'acpiosi=! acpi_osi=! acpi_osi="Windows 2000"' is
equivalent to
'acpi_osi=! acpi_osi=! acpi_osi="Windows 2000"'
and
'acpi_osi=! acpi_osi="Windows 2000" acpi_osi=!',
they all will make '_OSI("Windows 2000")' TRUE.
http://redsymbol.net/linux-kernel-boot-parameters/