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Friday, 8 January 2010

Exploring a DSDT.dsl file

This is a useful terminal command to explore DSDT.dsl files for laptop models that still don't have Linux switchable graphics support:

grep -n -e Device -e Notify -e VGA -e AGP -e PCI -e '^^' -e DSM -e TPX DSDT.dsl

Some of the currently supported methods are:
status = acpi_get_handle(root_handle, "\\_SB.PCI0.P0P1.VGA._OFF", &handle);
status = acpi_get_handle(root_handle, "\\_SB_.PCI0.OVGA.ATPX", &handle);
status = acpi_get_handle(root_handle, "\\_SB_.PCI0.OVGA.XTPX", &handle);

For example, by inspecting the DSDT.dsl file for a HP Pavilion dm3 1020ec, a variation of one of this ACPI methods shows up as the possible solution for switching on/off the Radeon HD 3200 series discrete graphics card:


Hopefully more and more DSDT.dsl files will be prompty supported, and the switchable graphics capability will be swiftly implemented starting from already existing modules.