Comment 289 for bug 59695

Your drive probably has something unique (and probably nonstandard)
about its power management settings that is preventing the hdparm
setting from taking. Whether it's a bug or an issue of the drive maker
not following standards, it appears hdparm isn't working quite right on
your system in regard to APM, and you should file a report on the hdparm
package.

I think the solutions we've been working toward here do actually work,
but not in cases where the power management cannot be controlled
(because both the issue and the workaround fix are directly related to
power management).