libata: disable LPM for some WD SATA-I devices

commit ecd75ad514d73efc1bbcc5f10a13566c3ace5f53 upstream.

For some reason, some early WD drives spin up and down drives
erratically when the link is put into slumber mode which can reduce
the life expectancy of the device significantly.  Unfortunately, we
don't have full list of devices and given the nature of the issue it'd
be better to err on the side of false positives than the other way
around.  Let's disable LPM on all WD devices which match one of the
known problematic model prefixes and are SATA-I.

As horkage list doesn't support matching SATA capabilities, this is
implemented as two horkages - WD_BROKEN_LPM and NOLPM.  The former is
set for the known prefixes and sets the latter if the matched device
is SATA-I.

Note that this isn't optimal as this disables all LPM operations and
partial link power state reportedly works fine on these; however, the
way LPM is implemented in libata makes it difficult to precisely map
libata LPM setting to specific link power state.  Well, these devices
are already fairly outdated.  Let's just disable whole LPM for now.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-and-tested-by: Nikos Barkas <levelwol@gmail.com>
Reported-and-tested-by: Ioannis Barkas <risc4all@yahoo.com>
References: https://bugzilla.kernel.org/show_bug.cgi?id=57211
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

0 files changed, 0 insertions, 0 deletions