Re: [PATCH] crypto: qce - Remove driver

[Eric Biggers <ebiggers@kernel.org>]

On Wed, Jul 29, 2026 at 06:55:20PM +0200, Konrad Dybcio wrote:
> >> Unfortunately removing it drains way more battery, because the buses
> >> never hit sync_state and are kept at their maximum frequencies:
> >>
> >> [   18.021823] qnoc-glymur interconnect-1: sync_state() pending due to 1dfa000.crypto
> >> [   18.029605] qnoc-glymur 16e0000.interconnect: sync_state() pending due to 1dfa000.crypto
> >>
> >> (it transiently also pins DRAM and friends to max-freq which absolutely
> >> kills battery life)
> > 
> > Isn't that easily fixable by marking the node as "disabled" in the
> > device tree, or even just deleting it entirely?
> 
> Avoided? Yes. Fixed? No. The DT is valid but Linux can't deal with it
> [since the driver is gone]

If needed we can keep a stub driver that just disables power and doesn't
register anything with the crypto API.  I can send a patch that does
that.

This is an interesting twist though, because it means the claim that
people can just disable this driver in their kconfig to avoid the
problems in it (which is being used as justification for keeping it) is
actually false as well.  As well as the claim that adding the node to
the DT file is "just describing the hardware" and has no impact.

This would also imply that no driver using this sync_state mechanism can
ever be completely removed from Linux, ever, which seems odd.

- Eric