On Mon, Mar 21, 2022 at 11:57 PM Damien Le Moal
<damien.lemoal@xxxxxxxxxxxxxxxxxx> wrote:
>
> * Rename ahci_board_mobile to board_ahci_low_power to be more descriptive
> of the feature as that is also used on PC and server AHCI adapters,
> from Mario.
>
> Mario Limonciello (3):
> ata: ahci: Rename board_ahci_mobile
> ata: ahci: Rename `AHCI_HFLAG_IS_MOBILE`
> ata: ahci: Rename CONFIG_SATA_LPM_MOBILE_POLICY configuration item
So I've pulled this, but it's worth noting that particularly renaming
that CONFIG option was probably not a good idea.
Why?
Because it means that people silently lose their old values. And it has that
range 0 4
default 0
with 4 being explicitly marked as very dangerous - but at least Fedora
seems to actually have a default of 3 in their kernels:
/boot/config-5.16.13-200.fc35.x86_64:
CONFIG_SATA_MOBILE_LPM_POLICY=3
so that "default 0" may actually not be the right one.
Now, we're at the point where few enough people likely care about ATA,
but the corollary to that is also that these kinds of changes can
cause user pain that then developers have *no* idea about.
Particularly when the pain ends up being caused by some subtle default
config option silently changing that nobody even thought about.
Now, that "default 0" is probably the only safe default - and I don't
dispute that part. But I also suspect that Fedora chose that value '3'
because it probably makes a noticeable power use difference on at
least some platforms.
I don't know. But I doubt really *anybody* knows, so renaming them and
silently likely changing config options for some less-than-critical
reason is just not a great idea.
Linus
