Re: [PATCH v5 03/13] mmc: arm_pl180: Gate idle card clocks

On Mon, Aug 24, 2026 at 3:25 PM Stephan Gerhold
<[email protected]> wrote:

> I'm not so sure about enabling PWRSAV, given that even Linux keeps that
> disabled. See mmci_set_clkreg():
>
>                 clk |= MCI_CLK_ENABLE;
>                 /* This hasn't proven to be worthwhile */
>                 /* clk |= MCI_CLK_PWRSAVE; */
>
> Which is BTW your own change from 2009. :-)
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=a6a6464a0ecd20c5f1594a4fe5b24af6181b7366

Yeah I dug in my old mail archive and I remember why this happened
like that actually.

I had a very sensitive Ampèremeter connected to the Ux500 prototype
platform and it didn't show any power improvement at all. The actual
clock gating at the clock source however did... it may be a bit dependent
on the interconnect and that's why I left it commented out, but let's
drop it.

Yours,
Linus Walleij