On certain implementations, _GTF evaluation depends on preceding _STM
and both can be pretty picky about the configuration. Using _GTM
result cached during controller initialization satisfies the most
neurotic _STM implementation. However, libata evaluates _GTF after
reset during device configuration and the hardware state can be
different from what _GTF expects and can cause evaluation failure.
This patch adds dev->gtf_cache and updates ata_dev_get_GTF() such that
it uses the cached value if available. Cache is cleared with a call
to ata_acpi_clear_gtf().
Because for SATA ACPI nodes _GTF must be evaluated after _SDD which
can't be done till IDENTIFY is complete, _GTF caching from
ata_acpi_on_resume() is used only for IDE ACPI nodes.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
398e07826b