Commit 1527f692 ("ata: ahci: Add Green Sardine vendor ID as
board_ahci_mobile") added an explicit entry for AMD Green Sardine
AHCI controller using the board_ahci_mobile configuration (this
configuration has later been renamed to board_ahci_low_power).

The board_ahci_low_power configuration enables support for low power
modes.

This explicit entry takes precedence over the generic AHCI controller
entry, which does not enable support for low power modes.

Therefore, when commit 1527f692 ("ata: ahci: Add Green Sardine
vendor ID as board_ahci_mobile") was backported to stable kernels,
it make some Pioneer optical drives, which was working perfectly fine
before the commit was backported, stop working.

The real problem is that the Pioneer optical drives do not handle low
power modes correctly. If these optical drives would have been tested
on another AHCI controller using the board_ahci_low_power configuration,
this issue would have been detected earlier.

Unfortunately, the board_ahci_low_power configuration is only used in
less than 15% of the total AHCI controller entries, so many devices
have never been tested with an AHCI controller with low power modes.

Fixes: 1527f692 ("ata: ahci: Add Green Sardine vendor ID as board_ahci_mobile")
Cc: stable@vger.kernel.org
Reported-by: Jaap Berkhout <j.j.berkhout@staalenberk.nl>
Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>