On Sunday 07 October 2007, Rafael J. Wysocki wrote:
CONFIG_BLK_DEV_IDEACPI=y is not enough since IDE ACPI _GTF support is disabled
by default. To enable it "ide=acpigtf" kernel parameter should be used.
Sometimes it may be also worth to try enabling usage of IDE ACPI methods on
boot ("ide=acpionboot" kernel parameter) which is also disabled by default.
We probably should switch both options to be on by default if recent libata
transition to ACPI on by default turns out to be successful.
PS I've updated bug #4580 accordingly.