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    SubjectRe: [PATCH] docs: driver-api: firmware: add driver firmware guidelines.
    On Mon, Jul 18, 2022 at 05:21:44PM +1000, Dave Airlie wrote:
    > From: Dave Airlie <airlied@redhat.com>
    >
    > A recent snafu where Intel ignored upstream feedback on a firmware
    > change, led to a late rc6 fix being required. In order to avoid this
    > in the future we should document some expectations around
    > linux-firmware.
    >
    > I was originally going to write this for drm, but it seems quite generic
    > advice.
    >
    > I'm cc'ing this quite widely to reach subsystems which use fw a lot.
    >
    > Signed-off-by: Dave Airlie <airlied@redhat.com>
    > ---
    > Documentation/driver-api/firmware/core.rst | 1 +
    > .../firmware/firmware-usage-guidelines.rst | 34 +++++++++++++++++++
    > 2 files changed, 35 insertions(+)
    > create mode 100644 Documentation/driver-api/firmware/firmware-usage-guidelines.rst
    >
    > diff --git a/Documentation/driver-api/firmware/core.rst b/Documentation/driver-api/firmware/core.rst
    > index 1d1688cbc078..803cd574bbd7 100644
    > --- a/Documentation/driver-api/firmware/core.rst
    > +++ b/Documentation/driver-api/firmware/core.rst
    > @@ -13,4 +13,5 @@ documents these features.
    > direct-fs-lookup
    > fallback-mechanisms
    > lookup-order
    > + firmware-usage-guidelines
    >
    > diff --git a/Documentation/driver-api/firmware/firmware-usage-guidelines.rst b/Documentation/driver-api/firmware/firmware-usage-guidelines.rst
    > new file mode 100644
    > index 000000000000..34d2412e78c6
    > --- /dev/null
    > +++ b/Documentation/driver-api/firmware/firmware-usage-guidelines.rst
    > @@ -0,0 +1,34 @@
    > +===================
    > +Firmware Guidelines
    > +===================
    > +
    > +Drivers that use firmware from linux-firmware should attempt to follow
    > +the rules in this guide.
    > +
    > +* Firmware should be versioned with at least a major/minor version. It
    > + is suggested that the firmware files in linux-firmware be named with
    > + some device specific name, and just the major version. The
    > + major/minor/patch versions should be stored in a header in the
    > + firmware file for the driver to detect any non-ABI fixes/issues. The
    > + firmware files in linux-firmware should be overwritten with the newest
    > + compatible major version. Newer major version firmware should remain
    > + compatible with all kernels that load that major number.

    would symbolic links be acceptable in the linux-firmware.git where
    the <fmw>_<major>.bin is a sym link to <fwm>_<major>.<minor>.bin

    or having the <fwm>_<major>.bin really to be the overwritten every minor
    update?

    > +
    > +* Users should *not* have to install newer firmware to use existing
    > + hardware when they install a newer kernel. If the hardware isn't
    > + enabled by default or under development, this can be ignored, until
    > + the first kernel release that enables that hardware. This means no
    > + major version bumps without the kernel retaining backwards
    > + compatibility for the older major versions. Minor version bumps
    > + should not introduce new features that newer kernels depend on
    > + non-optionally.
    > +
    > +* If a security fix needs lockstep firmware and kernel fixes in order to
    > + be successful, then all supported major versions in the linux-firmware
    > + repo should be updated with the security fix, and the kernel patches
    > + should detect if the firmware is new enough to declare if the security
    > + issue is fixed. All communications around security fixes should point
    > + at both the firmware and kernel fixes. If a security fix requires
    > + deprecating old major versions, then this should only be done as a
    > + last option, and be stated clearly in all communications.

    Everything makes sense to me. Thanks for writing this down.

    Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

    > +
    > --
    > 2.36.1
    >
    >
    >
    > --
    > _______________________________________________
    > Dri-devel mailing list
    > Dri-devel@lists.sourceforge.net
    > https://lists.sourceforge.net/lists/listinfo/dri-devel

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