lkml.org 
[lkml]   [2022]   [Jul]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH] docs: driver-api: firmware: add driver firmware guidelines.
    Date
    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.
    +
    +* 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.
    +
    --
    2.36.1
    \
     
     \ /
      Last update: 2022-07-18 09:23    [W:9.289 / U:0.040 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site