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

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

[Jacek Lawrynowicz]

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@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
-- 
2.45.1

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

[Bagas Sanjaya]

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On Fri, Mar 14, 2025 at 11:01:36AM +0100, Jacek Lawrynowicz wrote:
> +* 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.

Is it implied that the firmware UAPI MUST be designed to be right in the
first time (attempt) as it MUST be supported indefinitely?

Anyway, the wording LGTM.

Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>

Thanks.

-- 
An old man doll... just what I always wanted! - Clara

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

[Jonathan Corbet]

Jacek Lawrynowicz <jacek.lawrynowicz@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@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

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

[Dave Airlie]

On Tue, 18 Mar 2025 at 08:53, Jonathan Corbet <corbet@lwn.net> wrote:
>
> Jacek Lawrynowicz <jacek.lawrynowicz@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@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?

LGTM,

Acked-by: Dave Airlie <airlied@redhat.com>

Dave.

>
> Thanks,
>
> jon

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

[Jonathan Corbet]

Dave Airlie <airlied@gmail.com> writes:

>> Dave, you're the only one with fingerprints on this document; is the
>> change OK with you?
>
> LGTM,
>
> Acked-by: Dave Airlie <airlied@redhat.com>

OK, applied - thanks.

jon