[PATCH] docs: driver-api: firmware: clarify userspace requirements

[Jonathan Corbet]

Jacek Lawrynowicz <jacek.lawrynowicz at linux.intel.com> writes:

> The guidelines mention that firmware updates can't break the kernel,
> but it doesn't state directly that they can't break userspace programs.
> Make it explicit that firmware updates cannot break UAPI.
>
> Signed-off-by: Jacek Lawrynowicz <jacek.lawrynowicz at linux.intel.com>
> ---
>  .../driver-api/firmware/firmware-usage-guidelines.rst        | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/Documentation/driver-api/firmware/firmware-usage-guidelines.rst b/Documentation/driver-api/firmware/firmware-usage-guidelines.rst
> index fdcfce42c6d28..5f8f13e2ee510 100644
> --- a/Documentation/driver-api/firmware/firmware-usage-guidelines.rst
> +++ b/Documentation/driver-api/firmware/firmware-usage-guidelines.rst
> @@ -42,3 +42,8 @@ then of course these rules will not apply strictly.)
>    deprecating old major versions, then this should only be done as a
>    last option, and be stated clearly in all communications.
>  
> +* Firmware files that affect the User API (UAPI) shall not introduce
> +  changes that break existing userspace programs. Updates to such firmware
> +  must ensure backward compatibility with existing userspace applications.
> +  This includes maintaining consistent interfaces and behaviors that
> +  userspace programs rely on.
> \ No newline at end of file

This ^^^^^^^^^^^^^^^^^^^^^^^^  is a good thing to avoid.  That can be
fixed up at apply time.

Dave, you're the only one with fingerprints on this document; is the
change OK with you?

Thanks,

jon