Re: [PATCH] firmware: arm_ffa: Treat missing FF-A feature on a platform as a probe miss

Sudeep Holla <[email protected]> Wed, 27 May 2026 10:09:11 +0100

Newsgroups	org.kernel.vger.linux-integrity,dev.linux.lists.kvmarm,org.infradead.lists.linux-arm-kernel,org.kernel.vger.linux-kernel,org.kernel.vger.linux-security-module
Message-ID	<20260527-sparkling-sloppy-muskrat-c1e4ac@sudeepholla>

On Tue, May 26, 2026 at 12:35:43PM -0700, Nathan Chancellor wrote:
> On Tue, May 26, 2026 at 11:36:49AM +0100, Sudeep Holla wrote:
> > When FF-A initialisation is driven from a platform device probe, systems
> > that do not implement FF-A can return -EOPNOTSUPP from the early transport
> > or version discovery paths. Driver core treats that as a matched probe
> > failure and prints:
> > 
> >   |  arm-ffa arm-ffa: probe with driver arm-ffa failed with error -95
> > 
> > That is noisy for a firmware interface that can be absent on otherwise
> > valid systems. Driver core already treats -ENODEV and -ENXIO as quiet
> > rejected matches, so translate only the early unsupported discovery cases
> > to -ENODEV. Keep later setup failures unchanged so real FF-A
> > initialisation problems are still reported as probe failures.
> > 
> > Reported-by: Nathan Chancellor <[email protected]>
> > Closes: https://lore.kernel.org/all/20260523001148.GA1319283@ax162
> > Signed-off-by: Sudeep Holla <[email protected]>
> 
> Appears to work for me.
> 
> Tested-by: Nathan Chancellor <[email protected]>
>

Thanks for reporting and testing. Much appreciated!

-- 
Regards,
Sudeep