[RFC] GuC firmware versioning change

[RFC] GuC firmware versioning change

[Jeff McGee]

The GuC firmware team is proposing a change to the firmware versioning scheme.
The goal is to more accurately track the firmware interface to help users
manage dependencies on that interface. The proposed scheme is based on
semver.org with some additions to handle branching.

The proposed version number would have 4 fields: BASE.MAJOR.MINOR.PATCH.
Contrast this with the 2 fields in the current version number: MAJOR.MINOR.
Side note, the current firmware encodes a BRANCH and CLIENT number as well, but
they have not been needed by i915. So a firmware released with the proposed
scheme would be named <platform>_guc_ver<base>_<major>_<minor>_<patch>.bin
(ex: skl_guc_ver1_5_4_7.bin) instead of the current
<platform>_guc_ver<major>_<minor>.bin (ex: skl_guc_ver9_33.bin).

The BASE number is an ID that is used to identify a set of releases in which
the MAJOR.MINOR.PATCH semantics are consistent. In other words, two releases
from the same BASE can be compared via their MAJOR.MINOR.PATCH to infer their
relationship as described below. Two releases from a different BASE cannot be
reliably compared. The BASE number facilitates arbitrary branching which can
create duplicate and/or disconnected MAJOR.MINOR.PATCH versions. This type of
branching is expected to be rare, and so BASE will rarely change. When a new
BASE is created, the MAJOR.MINOR.PATCH reset to starting values.

The MAJOR number conforms to the major in semver.org. It increments on a
backwards incompatible change of the interface. It resets to 1 on a change of
BASE. The MAJOR number basically works the same between the current and
proposed versioning schemes.

The MINOR number conforms to the minor in semver.org. It increments on a
backwards compatible change of the interface (new interfaces that are optional
to use). It will also increment on substantial new internal functionality that
doesn't affect the interface but should be called out to the user. It resets to
0 on a change of MAJOR. The MINOR number in the current versioning scheme
increments on any backwards compatible change. The proposed versioning scheme
breaks this into the MINOR number just described and the PATCH number below.

The PATCH number conforms to the patch in semver.org. It increments on a
backwards compatible internal change, usually a bug fix. It resets to 0 on a
change of MINOR.

The MAJOR.MINOR collectively define the interface version. Because the MINOR
may also increment on a substantial internal change, it doesn't always mark an
interface change, e.g. 4.5 and 4.6 may have identical interfaces. But the
determination of interface compatibility is unchanged, e.g. 4.6 is always
backwards compatible with 4.5.

Each MAJOR.MINOR may continue to receive internal fixes along a branch even
after the main branch for that BASE has moved on to another MAJOR.MINOR.
Releases from these fix-only branches increment only the PATCH number on that
MAJOR.MINOR, and therefore remain semantically consistent with the main branch.
No change of BASE is therefore needed. Consider an example:

v1.1.0.0   v1.1.0.1   v1.1.0.2   v1.1.1.0   v1.1.1.1
----O----------O----------O----------O----------O    <-- main adopts v1.1.1.x
                           \
                            \
                             \
                              O----------O     <-- fixes for interface v1.1.0.x
                          v1.1.0.3   v1.1.0.4

There is no need to change the BASE because the branching happened from the
last fix (v1.1.0.2) on the main branch prior to the change of interface
(v1.1.1.0). As long as only fixes are applied to v1.1.0.x, there is no risk of
version number clash. All of these release versions remain semantically
connected with one small caveat. If this set of release versions came
sequentially along a single branch, one could infer that the exact fixes in
v1.1.0.4 were inherited by v1.1.1.0. With this "hidden" branching, this may
not be true as in this example. One would need to review the v1.1.1.0 release
notes to check.

Please provide any feedback on the proposed change.

Thanks,
Jeff
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Re: [RFC] GuC firmware versioning change

[Jeff McGee]

Forgot to add some people on CC.

On Fri, Oct 12, 2018 at 01:24:30PM -0700, Jeff McGee wrote:
> The GuC firmware team is proposing a change to the firmware versioning scheme.
> The goal is to more accurately track the firmware interface to help users
> manage dependencies on that interface. The proposed scheme is based on
> semver.org with some additions to handle branching.
> 
> The proposed version number would have 4 fields: BASE.MAJOR.MINOR.PATCH.
> Contrast this with the 2 fields in the current version number: MAJOR.MINOR.
> Side note, the current firmware encodes a BRANCH and CLIENT number as well, but
> they have not been needed by i915. So a firmware released with the proposed
> scheme would be named <platform>_guc_ver<base>_<major>_<minor>_<patch>.bin
> (ex: skl_guc_ver1_5_4_7.bin) instead of the current
> <platform>_guc_ver<major>_<minor>.bin (ex: skl_guc_ver9_33.bin).
> 
> The BASE number is an ID that is used to identify a set of releases in which
> the MAJOR.MINOR.PATCH semantics are consistent. In other words, two releases
> from the same BASE can be compared via their MAJOR.MINOR.PATCH to infer their
> relationship as described below. Two releases from a different BASE cannot be
> reliably compared. The BASE number facilitates arbitrary branching which can
> create duplicate and/or disconnected MAJOR.MINOR.PATCH versions. This type of
> branching is expected to be rare, and so BASE will rarely change. When a new
> BASE is created, the MAJOR.MINOR.PATCH reset to starting values.
> 
> The MAJOR number conforms to the major in semver.org. It increments on a
> backwards incompatible change of the interface. It resets to 1 on a change of
> BASE. The MAJOR number basically works the same between the current and
> proposed versioning schemes.
> 
> The MINOR number conforms to the minor in semver.org. It increments on a
> backwards compatible change of the interface (new interfaces that are optional
> to use). It will also increment on substantial new internal functionality that
> doesn't affect the interface but should be called out to the user. It resets to
> 0 on a change of MAJOR. The MINOR number in the current versioning scheme
> increments on any backwards compatible change. The proposed versioning scheme
> breaks this into the MINOR number just described and the PATCH number below.
> 
> The PATCH number conforms to the patch in semver.org. It increments on a
> backwards compatible internal change, usually a bug fix. It resets to 0 on a
> change of MINOR.
> 
> The MAJOR.MINOR collectively define the interface version. Because the MINOR
> may also increment on a substantial internal change, it doesn't always mark an
> interface change, e.g. 4.5 and 4.6 may have identical interfaces. But the
> determination of interface compatibility is unchanged, e.g. 4.6 is always
> backwards compatible with 4.5.
> 
> Each MAJOR.MINOR may continue to receive internal fixes along a branch even
> after the main branch for that BASE has moved on to another MAJOR.MINOR.
> Releases from these fix-only branches increment only the PATCH number on that
> MAJOR.MINOR, and therefore remain semantically consistent with the main branch.
> No change of BASE is therefore needed. Consider an example:
> 
> v1.1.0.0   v1.1.0.1   v1.1.0.2   v1.1.1.0   v1.1.1.1
> ----O----------O----------O----------O----------O    <-- main adopts v1.1.1.x
>                            \
>                             \
>                              \
>                               O----------O     <-- fixes for interface v1.1.0.x
>                           v1.1.0.3   v1.1.0.4
> 
> There is no need to change the BASE because the branching happened from the
> last fix (v1.1.0.2) on the main branch prior to the change of interface
> (v1.1.1.0). As long as only fixes are applied to v1.1.0.x, there is no risk of
> version number clash. All of these release versions remain semantically
> connected with one small caveat. If this set of release versions came
> sequentially along a single branch, one could infer that the exact fixes in
> v1.1.0.4 were inherited by v1.1.1.0. With this "hidden" branching, this may
> not be true as in this example. One would need to review the v1.1.1.0 release
> notes to check.
> 
> Please provide any feedback on the proposed change.
> 
> Thanks,
> Jeff
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
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Re: [RFC] GuC firmware versioning change

[Rodrigo Vivi]

On Fri, Oct 12, 2018 at 01:24:30PM -0700, Jeff McGee wrote:
> The GuC firmware team is proposing a change to the firmware versioning scheme.
> The goal is to more accurately track the firmware interface to help users
> manage dependencies on that interface. The proposed scheme is based on
> semver.org with some additions to handle branching.
> 
> The proposed version number would have 4 fields: BASE.MAJOR.MINOR.PATCH.
> Contrast this with the 2 fields in the current version number: MAJOR.MINOR.
> Side note, the current firmware encodes a BRANCH and CLIENT number as well, but
> they have not been needed by i915. So a firmware released with the proposed
> scheme would be named <platform>_guc_ver<base>_<major>_<minor>_<patch>.bin
> (ex: skl_guc_ver1_5_4_7.bin) instead of the current
> <platform>_guc_ver<major>_<minor>.bin (ex: skl_guc_ver9_33.bin).
> 
> The BASE number is an ID that is used to identify a set of releases in which
> the MAJOR.MINOR.PATCH semantics are consistent. In other words, two releases
> from the same BASE can be compared via their MAJOR.MINOR.PATCH to infer their
> relationship as described below. Two releases from a different BASE cannot be
> reliably compared. The BASE number facilitates arbitrary branching which can
> create duplicate and/or disconnected MAJOR.MINOR.PATCH versions. This type of
> branching is expected to be rare, and so BASE will rarely change. When a new
> BASE is created, the MAJOR.MINOR.PATCH reset to starting values.

Could you please clarify a bit what BASE means?
What would be a different BASE?

> 
> The MAJOR number conforms to the major in semver.org. It increments on a
> backwards incompatible change of the interface. It resets to 1 on a change of
> BASE. The MAJOR number basically works the same between the current and
> proposed versioning schemes.
> 
> The MINOR number conforms to the minor in semver.org. It increments on a
> backwards compatible change of the interface (new interfaces that are optional
> to use). It will also increment on substantial new internal functionality that
> doesn't affect the interface but should be called out to the user. It resets to
> 0 on a change of MAJOR. The MINOR number in the current versioning scheme
> increments on any backwards compatible change. The proposed versioning scheme
> breaks this into the MINOR number just described and the PATCH number below.
> 
> The PATCH number conforms to the patch in semver.org. It increments on a
> backwards compatible internal change, usually a bug fix. It resets to 0 on a
> change of MINOR.

I like the idea of MAJOR.MINOR.PATCH following semver.org.

I think if we remove the BASE out of picture and just use semver clear,
but maybe it is just because I didn't quite understand BASE.

> 
> The MAJOR.MINOR collectively define the interface version. Because the MINOR
> may also increment on a substantial internal change, it doesn't always mark an
> interface change, e.g. 4.5 and 4.6 may have identical interfaces. But the
> determination of interface compatibility is unchanged, e.g. 4.6 is always
> backwards compatible with 4.5.
> 
> Each MAJOR.MINOR may continue to receive internal fixes along a branch even
> after the main branch for that BASE has moved on to another MAJOR.MINOR.
> Releases from these fix-only branches increment only the PATCH number on that
> MAJOR.MINOR, and therefore remain semantically consistent with the main branch.
> No change of BASE is therefore needed. Consider an example:
> 
> v1.1.0.0   v1.1.0.1   v1.1.0.2   v1.1.1.0   v1.1.1.1
> ----O----------O----------O----------O----------O    <-- main adopts v1.1.1.x
>                            \
>                             \
>                              \
>                               O----------O     <-- fixes for interface v1.1.0.x
>                           v1.1.0.3   v1.1.0.4

This approach is cool and more or less how Mesa handles their releases,
except by the fact that their Major is the year and minor is the month.

However, on the firmware side I have a concern because we are so far trying
to make sure that we have 1-1 relationship on kernel-firmware version.

But based on this view and what Anusha told me yesterday it seems
that GuC is getting constant releases. With the constant patches we will
soon explode linux-firmware.git repository size.

But this maybe is something to be solved on linux-firmware side and we make
sure that we clean up and remove firmware that were never released in any
official Linux kernel. Anusha or Antonio, thoughts?

Thanks,
Rodrigo.

> 
> There is no need to change the BASE because the branching happened from the
> last fix (v1.1.0.2) on the main branch prior to the change of interface
> (v1.1.1.0). As long as only fixes are applied to v1.1.0.x, there is no risk of
> version number clash. All of these release versions remain semantically
> connected with one small caveat. If this set of release versions came
> sequentially along a single branch, one could infer that the exact fixes in
> v1.1.0.4 were inherited by v1.1.1.0. With this "hidden" branching, this may
> not be true as in this example. One would need to review the v1.1.1.0 release
> notes to check.
> 
> Please provide any feedback on the proposed change.
> 
> Thanks,
> Jeff
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Re: [RFC] GuC firmware versioning change

[Jeff McGee]

On Fri, Oct 12, 2018 at 01:51:46PM -0700, Rodrigo Vivi wrote:
> On Fri, Oct 12, 2018 at 01:24:30PM -0700, Jeff McGee wrote:
> > The GuC firmware team is proposing a change to the firmware versioning scheme.
> > The goal is to more accurately track the firmware interface to help users
> > manage dependencies on that interface. The proposed scheme is based on
> > semver.org with some additions to handle branching.
> > 
> > The proposed version number would have 4 fields: BASE.MAJOR.MINOR.PATCH.
> > Contrast this with the 2 fields in the current version number: MAJOR.MINOR.
> > Side note, the current firmware encodes a BRANCH and CLIENT number as well, but
> > they have not been needed by i915. So a firmware released with the proposed
> > scheme would be named <platform>_guc_ver<base>_<major>_<minor>_<patch>.bin
> > (ex: skl_guc_ver1_5_4_7.bin) instead of the current
> > <platform>_guc_ver<major>_<minor>.bin (ex: skl_guc_ver9_33.bin).
> > 
> > The BASE number is an ID that is used to identify a set of releases in which
> > the MAJOR.MINOR.PATCH semantics are consistent. In other words, two releases
> > from the same BASE can be compared via their MAJOR.MINOR.PATCH to infer their
> > relationship as described below. Two releases from a different BASE cannot be
> > reliably compared. The BASE number facilitates arbitrary branching which can
> > create duplicate and/or disconnected MAJOR.MINOR.PATCH versions. This type of
> > branching is expected to be rare, and so BASE will rarely change. When a new
> > BASE is created, the MAJOR.MINOR.PATCH reset to starting values.
> 
> Could you please clarify a bit what BASE means?
> What would be a different BASE?
> 

The BASE number supports general branching that would cause version number
conflicts. Branching for firmware releases is not desirable, but it is a
practical reality. Therefore the versioning scheme must accomodate it. Let's
say that a high-priority request is made to put specific updates on an old
release that said customer is locked on. Those updates could include any sort
of change including interface change. Then we have a sequence like below:

v1.1.0.0   v1.1.0.1   v1.1.0.2   v1.1.0.3   v1.1.1.0
----O----------O----------O----------O----------O
                           \
                            \
                             \
                              O----------O
                          v2.1.1.0   v2.1.1.1

You can see that if we don't have a BASE number that changes from 1 to 2, then
we end up with duplicated v1.1.0 along the different branches which are not the
same. As I wrote, this should be a very rare scenario, but it can happen. Maybe
upstream will always be supplied with releases from the "main" BASE, and you
can ignore this field, but it needs to be there for other firmware
distributions.
-Jeff

> > 
> > The MAJOR number conforms to the major in semver.org. It increments on a
> > backwards incompatible change of the interface. It resets to 1 on a change of
> > BASE. The MAJOR number basically works the same between the current and
> > proposed versioning schemes.
> > 
> > The MINOR number conforms to the minor in semver.org. It increments on a
> > backwards compatible change of the interface (new interfaces that are optional
> > to use). It will also increment on substantial new internal functionality that
> > doesn't affect the interface but should be called out to the user. It resets to
> > 0 on a change of MAJOR. The MINOR number in the current versioning scheme
> > increments on any backwards compatible change. The proposed versioning scheme
> > breaks this into the MINOR number just described and the PATCH number below.
> > 
> > The PATCH number conforms to the patch in semver.org. It increments on a
> > backwards compatible internal change, usually a bug fix. It resets to 0 on a
> > change of MINOR.
> 
> I like the idea of MAJOR.MINOR.PATCH following semver.org.
> 
> I think if we remove the BASE out of picture and just use semver clear,
> but maybe it is just because I didn't quite understand BASE.
> 
> > 
> > The MAJOR.MINOR collectively define the interface version. Because the MINOR
> > may also increment on a substantial internal change, it doesn't always mark an
> > interface change, e.g. 4.5 and 4.6 may have identical interfaces. But the
> > determination of interface compatibility is unchanged, e.g. 4.6 is always
> > backwards compatible with 4.5.
> > 
> > Each MAJOR.MINOR may continue to receive internal fixes along a branch even
> > after the main branch for that BASE has moved on to another MAJOR.MINOR.
> > Releases from these fix-only branches increment only the PATCH number on that
> > MAJOR.MINOR, and therefore remain semantically consistent with the main branch.
> > No change of BASE is therefore needed. Consider an example:
> > 
> > v1.1.0.0   v1.1.0.1   v1.1.0.2   v1.1.1.0   v1.1.1.1
> > ----O----------O----------O----------O----------O    <-- main adopts v1.1.1.x
> >                            \
> >                             \
> >                              \
> >                               O----------O     <-- fixes for interface v1.1.0.x
> >                           v1.1.0.3   v1.1.0.4
> 
> This approach is cool and more or less how Mesa handles their releases,
> except by the fact that their Major is the year and minor is the month.
> 
> However, on the firmware side I have a concern because we are so far trying
> to make sure that we have 1-1 relationship on kernel-firmware version.
> 
> But based on this view and what Anusha told me yesterday it seems
> that GuC is getting constant releases. With the constant patches we will
> soon explode linux-firmware.git repository size.
> 
> But this maybe is something to be solved on linux-firmware side and we make
> sure that we clean up and remove firmware that were never released in any
> official Linux kernel. Anusha or Antonio, thoughts?
> 
> Thanks,
> Rodrigo.
> 

I expect that i915 will still require a single version of firmware per platform
as it does today. This change should not impact that other than to require i915
to check 4 numbers instead of 2.

It is true that firmware releases are made *internally* (from the firmware
team to the operating system teams) at a frequent rate. It is up to each OS
team to decide their own cadence for integrating and distributing those
firmware based on their unique situation. So the Linux team may filter these
releases and update the upstream much less frequently.

> > 
> > There is no need to change the BASE because the branching happened from the
> > last fix (v1.1.0.2) on the main branch prior to the change of interface
> > (v1.1.1.0). As long as only fixes are applied to v1.1.0.x, there is no risk of
> > version number clash. All of these release versions remain semantically
> > connected with one small caveat. If this set of release versions came
> > sequentially along a single branch, one could infer that the exact fixes in
> > v1.1.0.4 were inherited by v1.1.1.0. With this "hidden" branching, this may
> > not be true as in this example. One would need to review the v1.1.1.0 release
> > notes to check.
> > 
> > Please provide any feedback on the proposed change.
> > 
> > Thanks,
> > Jeff
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Re: [RFC] GuC firmware versioning change

[Jeff McGee]

On Fri, Oct 12, 2018 at 02:33:26PM -0700, Jeff McGee wrote:
> On Fri, Oct 12, 2018 at 01:51:46PM -0700, Rodrigo Vivi wrote:
> > On Fri, Oct 12, 2018 at 01:24:30PM -0700, Jeff McGee wrote:
> > > The GuC firmware team is proposing a change to the firmware versioning scheme.
> > > The goal is to more accurately track the firmware interface to help users
> > > manage dependencies on that interface. The proposed scheme is based on
> > > semver.org with some additions to handle branching.
> > > 
> > > The proposed version number would have 4 fields: BASE.MAJOR.MINOR.PATCH.
> > > Contrast this with the 2 fields in the current version number: MAJOR.MINOR.
> > > Side note, the current firmware encodes a BRANCH and CLIENT number as well, but
> > > they have not been needed by i915. So a firmware released with the proposed
> > > scheme would be named <platform>_guc_ver<base>_<major>_<minor>_<patch>.bin
> > > (ex: skl_guc_ver1_5_4_7.bin) instead of the current
> > > <platform>_guc_ver<major>_<minor>.bin (ex: skl_guc_ver9_33.bin).
> > > 
> > > The BASE number is an ID that is used to identify a set of releases in which
> > > the MAJOR.MINOR.PATCH semantics are consistent. In other words, two releases
> > > from the same BASE can be compared via their MAJOR.MINOR.PATCH to infer their
> > > relationship as described below. Two releases from a different BASE cannot be
> > > reliably compared. The BASE number facilitates arbitrary branching which can
> > > create duplicate and/or disconnected MAJOR.MINOR.PATCH versions. This type of
> > > branching is expected to be rare, and so BASE will rarely change. When a new
> > > BASE is created, the MAJOR.MINOR.PATCH reset to starting values.
> > 
> > Could you please clarify a bit what BASE means?
> > What would be a different BASE?
> > 
> 
> The BASE number supports general branching that would cause version number
> conflicts. Branching for firmware releases is not desirable, but it is a
> practical reality. Therefore the versioning scheme must accomodate it. Let's
> say that a high-priority request is made to put specific updates on an old
> release that said customer is locked on. Those updates could include any sort
> of change including interface change. Then we have a sequence like below:
> 
> v1.1.0.0   v1.1.0.1   v1.1.0.2   v1.1.0.3   v1.1.1.0
> ----O----------O----------O----------O----------O
>                            \
>                             \
>                              \
>                               O----------O
>                           v2.1.1.0   v2.1.1.1
> 
> You can see that if we don't have a BASE number that changes from 1 to 2, then
> we end up with duplicated v1.1.0 along the different branches which are not the
> same. As I wrote, this should be a very rare scenario, but it can happen. Maybe
> upstream will always be supplied with releases from the "main" BASE, and you
> can ignore this field, but it needs to be there for other firmware
> distributions.
> -Jeff
> 

Sorry, I misrepresented how to the numbers would change in the above example.
The change of BASE from 1 to 2 would reset MAJOR.MINOR.PATCH. So the sequence
should be v1.1.0.2 -> v2.1.0.0 -> v2.1.0.1 and so on.

If we don't have BASE, the pure semver.org sequence would be:

  v1.0.0     v1.0.1     v1.0.2     v1.0.3     v1.1.0
----O----------O----------O----------O----------O
                           \
                            \
                             \
                              O----------O
                            v1.1.0     v1.1.1

And so you see the duplication of version number.
- Jeff

> > > 
> > > The MAJOR number conforms to the major in semver.org. It increments on a
> > > backwards incompatible change of the interface. It resets to 1 on a change of
> > > BASE. The MAJOR number basically works the same between the current and
> > > proposed versioning schemes.
> > > 
> > > The MINOR number conforms to the minor in semver.org. It increments on a
> > > backwards compatible change of the interface (new interfaces that are optional
> > > to use). It will also increment on substantial new internal functionality that
> > > doesn't affect the interface but should be called out to the user. It resets to
> > > 0 on a change of MAJOR. The MINOR number in the current versioning scheme
> > > increments on any backwards compatible change. The proposed versioning scheme
> > > breaks this into the MINOR number just described and the PATCH number below.
> > > 
> > > The PATCH number conforms to the patch in semver.org. It increments on a
> > > backwards compatible internal change, usually a bug fix. It resets to 0 on a
> > > change of MINOR.
> > 
> > I like the idea of MAJOR.MINOR.PATCH following semver.org.
> > 
> > I think if we remove the BASE out of picture and just use semver clear,
> > but maybe it is just because I didn't quite understand BASE.
> > 
> > > 
> > > The MAJOR.MINOR collectively define the interface version. Because the MINOR
> > > may also increment on a substantial internal change, it doesn't always mark an
> > > interface change, e.g. 4.5 and 4.6 may have identical interfaces. But the
> > > determination of interface compatibility is unchanged, e.g. 4.6 is always
> > > backwards compatible with 4.5.
> > > 
> > > Each MAJOR.MINOR may continue to receive internal fixes along a branch even
> > > after the main branch for that BASE has moved on to another MAJOR.MINOR.
> > > Releases from these fix-only branches increment only the PATCH number on that
> > > MAJOR.MINOR, and therefore remain semantically consistent with the main branch.
> > > No change of BASE is therefore needed. Consider an example:
> > > 
> > > v1.1.0.0   v1.1.0.1   v1.1.0.2   v1.1.1.0   v1.1.1.1
> > > ----O----------O----------O----------O----------O    <-- main adopts v1.1.1.x
> > >                            \
> > >                             \
> > >                              \
> > >                               O----------O     <-- fixes for interface v1.1.0.x
> > >                           v1.1.0.3   v1.1.0.4
> > 
> > This approach is cool and more or less how Mesa handles their releases,
> > except by the fact that their Major is the year and minor is the month.
> > 
> > However, on the firmware side I have a concern because we are so far trying
> > to make sure that we have 1-1 relationship on kernel-firmware version.
> > 
> > But based on this view and what Anusha told me yesterday it seems
> > that GuC is getting constant releases. With the constant patches we will
> > soon explode linux-firmware.git repository size.
> > 
> > But this maybe is something to be solved on linux-firmware side and we make
> > sure that we clean up and remove firmware that were never released in any
> > official Linux kernel. Anusha or Antonio, thoughts?
> > 
> > Thanks,
> > Rodrigo.
> > 
> 
> I expect that i915 will still require a single version of firmware per platform
> as it does today. This change should not impact that other than to require i915
> to check 4 numbers instead of 2.
> 
> It is true that firmware releases are made *internally* (from the firmware
> team to the operating system teams) at a frequent rate. It is up to each OS
> team to decide their own cadence for integrating and distributing those
> firmware based on their unique situation. So the Linux team may filter these
> releases and update the upstream much less frequently.
> 
> > > 
> > > There is no need to change the BASE because the branching happened from the
> > > last fix (v1.1.0.2) on the main branch prior to the change of interface
> > > (v1.1.1.0). As long as only fixes are applied to v1.1.0.x, there is no risk of
> > > version number clash. All of these release versions remain semantically
> > > connected with one small caveat. If this set of release versions came
> > > sequentially along a single branch, one could infer that the exact fixes in
> > > v1.1.0.4 were inherited by v1.1.1.0. With this "hidden" branching, this may
> > > not be true as in this example. One would need to review the v1.1.1.0 release
> > > notes to check.
> > > 
> > > Please provide any feedback on the proposed change.
> > > 
> > > Thanks,
> > > Jeff
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
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Re: [RFC] GuC firmware versioning change

[Joonas Lahtinen]

Quoting Jeff McGee (2018-10-13 00:46:05)
> On Fri, Oct 12, 2018 at 02:33:26PM -0700, Jeff McGee wrote:
> > On Fri, Oct 12, 2018 at 01:51:46PM -0700, Rodrigo Vivi wrote:
> > > On Fri, Oct 12, 2018 at 01:24:30PM -0700, Jeff McGee wrote:
> > > > The GuC firmware team is proposing a change to the firmware versioning scheme.
> > > > The goal is to more accurately track the firmware interface to help users
> > > > manage dependencies on that interface. The proposed scheme is based on
> > > > semver.org with some additions to handle branching.
> > > > 
> > > > The proposed version number would have 4 fields: BASE.MAJOR.MINOR.PATCH.
> > > > Contrast this with the 2 fields in the current version number: MAJOR.MINOR.
> > > > Side note, the current firmware encodes a BRANCH and CLIENT number as well, but
> > > > they have not been needed by i915. So a firmware released with the proposed
> > > > scheme would be named <platform>_guc_ver<base>_<major>_<minor>_<patch>.bin
> > > > (ex: skl_guc_ver1_5_4_7.bin) instead of the current
> > > > <platform>_guc_ver<major>_<minor>.bin (ex: skl_guc_ver9_33.bin).
> > > > 
> > > > The BASE number is an ID that is used to identify a set of releases in which
> > > > the MAJOR.MINOR.PATCH semantics are consistent. In other words, two releases
> > > > from the same BASE can be compared via their MAJOR.MINOR.PATCH to infer their
> > > > relationship as described below. Two releases from a different BASE cannot be
> > > > reliably compared. The BASE number facilitates arbitrary branching which can
> > > > create duplicate and/or disconnected MAJOR.MINOR.PATCH versions. This type of
> > > > branching is expected to be rare, and so BASE will rarely change. When a new
> > > > BASE is created, the MAJOR.MINOR.PATCH reset to starting values.
> > > 
> > > Could you please clarify a bit what BASE means?
> > > What would be a different BASE?
> > > 
> > 
> > The BASE number supports general branching that would cause version number
> > conflicts. Branching for firmware releases is not desirable, but it is a
> > practical reality. Therefore the versioning scheme must accomodate it. Let's
> > say that a high-priority request is made to put specific updates on an old
> > release that said customer is locked on. Those updates could include any sort
> > of change including interface change. Then we have a sequence like below:
> > 
> > v1.1.0.0   v1.1.0.1   v1.1.0.2   v1.1.0.3   v1.1.1.0
> > ----O----------O----------O----------O----------O
> >                            \
> >                             \
> >                              \
> >                               O----------O
> >                           v2.1.1.0   v2.1.1.1
> > 
> > You can see that if we don't have a BASE number that changes from 1 to 2, then
> > we end up with duplicated v1.1.0 along the different branches which are not the
> > same. As I wrote, this should be a very rare scenario, but it can happen. Maybe
> > upstream will always be supplied with releases from the "main" BASE, and you
> > can ignore this field, but it needs to be there for other firmware
> > distributions.

I thought we covered this in some meeting already. Anyway, I very much
agree with Rodrigo that adding BASE sounds like extra complication.

In upstream code, we would only care about latest according to
semver aka. the bleeding edge firmware. As those are the only
firmwares to be dropped to linux-firmware repo, there should
be no need for BASE in the versioning for upstream.

The problem you're trying to solve is revisioning forks, and
the upstream interface should not track forks but it will always
follow the latest bleeding edge. Whoever decides to fork the
upstream code, can add the code for the BASE named firmwares.

If there won't be a clear bleeding edge firmware with MAJOR
incrementing linearly on backwards breaking changes (which
should be minimized), which can easily be understood by the
upstream kernel consumers, then we will have more confusion
than is necessary.

Regards, Joonas

> > -Jeff
> > 
> 
> Sorry, I misrepresented how to the numbers would change in the above example.
> The change of BASE from 1 to 2 would reset MAJOR.MINOR.PATCH. So the sequence
> should be v1.1.0.2 -> v2.1.0.0 -> v2.1.0.1 and so on.
> 
> If we don't have BASE, the pure semver.org sequence would be:
> 
>   v1.0.0     v1.0.1     v1.0.2     v1.0.3     v1.1.0
> ----O----------O----------O----------O----------O
>                            \
>                             \
>                              \
>                               O----------O
>                             v1.1.0     v1.1.1
> 
> And so you see the duplication of version number.
> - Jeff
> 
> > > > 
> > > > The MAJOR number conforms to the major in semver.org. It increments on a
> > > > backwards incompatible change of the interface. It resets to 1 on a change of
> > > > BASE. The MAJOR number basically works the same between the current and
> > > > proposed versioning schemes.
> > > > 
> > > > The MINOR number conforms to the minor in semver.org. It increments on a
> > > > backwards compatible change of the interface (new interfaces that are optional
> > > > to use). It will also increment on substantial new internal functionality that
> > > > doesn't affect the interface but should be called out to the user. It resets to
> > > > 0 on a change of MAJOR. The MINOR number in the current versioning scheme
> > > > increments on any backwards compatible change. The proposed versioning scheme
> > > > breaks this into the MINOR number just described and the PATCH number below.
> > > > 
> > > > The PATCH number conforms to the patch in semver.org. It increments on a
> > > > backwards compatible internal change, usually a bug fix. It resets to 0 on a
> > > > change of MINOR.
> > > 
> > > I like the idea of MAJOR.MINOR.PATCH following semver.org.
> > > 
> > > I think if we remove the BASE out of picture and just use semver clear,
> > > but maybe it is just because I didn't quite understand BASE.
> > > 
> > > > 
> > > > The MAJOR.MINOR collectively define the interface version. Because the MINOR
> > > > may also increment on a substantial internal change, it doesn't always mark an
> > > > interface change, e.g. 4.5 and 4.6 may have identical interfaces. But the
> > > > determination of interface compatibility is unchanged, e.g. 4.6 is always
> > > > backwards compatible with 4.5.
> > > > 
> > > > Each MAJOR.MINOR may continue to receive internal fixes along a branch even
> > > > after the main branch for that BASE has moved on to another MAJOR.MINOR.
> > > > Releases from these fix-only branches increment only the PATCH number on that
> > > > MAJOR.MINOR, and therefore remain semantically consistent with the main branch.
> > > > No change of BASE is therefore needed. Consider an example:
> > > > 
> > > > v1.1.0.0   v1.1.0.1   v1.1.0.2   v1.1.1.0   v1.1.1.1
> > > > ----O----------O----------O----------O----------O    <-- main adopts v1.1.1.x
> > > >                            \
> > > >                             \
> > > >                              \
> > > >                               O----------O     <-- fixes for interface v1.1.0.x
> > > >                           v1.1.0.3   v1.1.0.4
> > > 
> > > This approach is cool and more or less how Mesa handles their releases,
> > > except by the fact that their Major is the year and minor is the month.
> > > 
> > > However, on the firmware side I have a concern because we are so far trying
> > > to make sure that we have 1-1 relationship on kernel-firmware version.
> > > 
> > > But based on this view and what Anusha told me yesterday it seems
> > > that GuC is getting constant releases. With the constant patches we will
> > > soon explode linux-firmware.git repository size.
> > > 
> > > But this maybe is something to be solved on linux-firmware side and we make
> > > sure that we clean up and remove firmware that were never released in any
> > > official Linux kernel. Anusha or Antonio, thoughts?
> > > 
> > > Thanks,
> > > Rodrigo.
> > > 
> > 
> > I expect that i915 will still require a single version of firmware per platform
> > as it does today. This change should not impact that other than to require i915
> > to check 4 numbers instead of 2.
> > 
> > It is true that firmware releases are made *internally* (from the firmware
> > team to the operating system teams) at a frequent rate. It is up to each OS
> > team to decide their own cadence for integrating and distributing those
> > firmware based on their unique situation. So the Linux team may filter these
> > releases and update the upstream much less frequently.
> > 
> > > > 
> > > > There is no need to change the BASE because the branching happened from the
> > > > last fix (v1.1.0.2) on the main branch prior to the change of interface
> > > > (v1.1.1.0). As long as only fixes are applied to v1.1.0.x, there is no risk of
> > > > version number clash. All of these release versions remain semantically
> > > > connected with one small caveat. If this set of release versions came
> > > > sequentially along a single branch, one could infer that the exact fixes in
> > > > v1.1.0.4 were inherited by v1.1.1.0. With this "hidden" branching, this may
> > > > not be true as in this example. One would need to review the v1.1.1.0 release
> > > > notes to check.
> > > > 
> > > > Please provide any feedback on the proposed change.
> > > > 
> > > > Thanks,
> > > > Jeff
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
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Re: [RFC] GuC firmware versioning change

[Daniel Vetter]

On Fri, Oct 12, 2018 at 11:45 PM Jeff McGee <jeff.mcgee@intel.com> wrote:
>
> On Fri, Oct 12, 2018 at 02:33:26PM -0700, Jeff McGee wrote:
> > On Fri, Oct 12, 2018 at 01:51:46PM -0700, Rodrigo Vivi wrote:
> > > On Fri, Oct 12, 2018 at 01:24:30PM -0700, Jeff McGee wrote:
> > > > The GuC firmware team is proposing a change to the firmware versioning scheme.
> > > > The goal is to more accurately track the firmware interface to help users
> > > > manage dependencies on that interface. The proposed scheme is based on
> > > > semver.org with some additions to handle branching.
> > > >
> > > > The proposed version number would have 4 fields: BASE.MAJOR.MINOR.PATCH.
> > > > Contrast this with the 2 fields in the current version number: MAJOR.MINOR.
> > > > Side note, the current firmware encodes a BRANCH and CLIENT number as well, but
> > > > they have not been needed by i915. So a firmware released with the proposed
> > > > scheme would be named <platform>_guc_ver<base>_<major>_<minor>_<patch>.bin
> > > > (ex: skl_guc_ver1_5_4_7.bin) instead of the current
> > > > <platform>_guc_ver<major>_<minor>.bin (ex: skl_guc_ver9_33.bin).
> > > >
> > > > The BASE number is an ID that is used to identify a set of releases in which
> > > > the MAJOR.MINOR.PATCH semantics are consistent. In other words, two releases
> > > > from the same BASE can be compared via their MAJOR.MINOR.PATCH to infer their
> > > > relationship as described below. Two releases from a different BASE cannot be
> > > > reliably compared. The BASE number facilitates arbitrary branching which can
> > > > create duplicate and/or disconnected MAJOR.MINOR.PATCH versions. This type of
> > > > branching is expected to be rare, and so BASE will rarely change. When a new
> > > > BASE is created, the MAJOR.MINOR.PATCH reset to starting values.
> > >
> > > Could you please clarify a bit what BASE means?
> > > What would be a different BASE?
> > >
> >
> > The BASE number supports general branching that would cause version number
> > conflicts. Branching for firmware releases is not desirable, but it is a
> > practical reality. Therefore the versioning scheme must accomodate it. Let's
> > say that a high-priority request is made to put specific updates on an old
> > release that said customer is locked on. Those updates could include any sort
> > of change including interface change. Then we have a sequence like below:
> >
> > v1.1.0.0   v1.1.0.1   v1.1.0.2   v1.1.0.3   v1.1.1.0
> > ----O----------O----------O----------O----------O
> >                            \
> >                             \
> >                              \
> >                               O----------O
> >                           v2.1.1.0   v2.1.1.1
> >
> > You can see that if we don't have a BASE number that changes from 1 to 2, then
> > we end up with duplicated v1.1.0 along the different branches which are not the
> > same. As I wrote, this should be a very rare scenario, but it can happen. Maybe
> > upstream will always be supplied with releases from the "main" BASE, and you
> > can ignore this field, but it needs to be there for other firmware
> > distributions.

The way this is usually solved in semver is to not prepend a BASE, but
postfix a branch-specific version, while keeping the mainline version
unchanged. So

v2.1.1.0 becomes v1.1.0.1-branch1-0
v2.1.1.1 becomes v1.1.0.1-branch1-1

With the rule that branches are explicitly unsorted (that's denoted by
the - - around them, instead o using dots), so not comparable. Bonus
points if you name the branch points by the customers (could be the
product, or internal customer group or whatever) to make these names
slightly more meaningful.

Prefixing a BASE, with a dot, is very much not how it's done and very
confusing. There's one thing debian does, it's prepending an EPOCH,
which is used for e.g. C++ packages when the compiler abi changes. I
think reading up on debian's rules would be good inspiration for this
problem:

https://serverfault.com/questions/604541/debian-packages-version-convention

Cheers, Daniel

> > -Jeff
> >
>
> Sorry, I misrepresented how to the numbers would change in the above example.
> The change of BASE from 1 to 2 would reset MAJOR.MINOR.PATCH. So the sequence
> should be v1.1.0.2 -> v2.1.0.0 -> v2.1.0.1 and so on.
>
> If we don't have BASE, the pure semver.org sequence would be:
>
>   v1.0.0     v1.0.1     v1.0.2     v1.0.3     v1.1.0
> ----O----------O----------O----------O----------O
>                            \
>                             \
>                              \
>                               O----------O
>                             v1.1.0     v1.1.1
>
> And so you see the duplication of version number.
> - Jeff
>
> > > >
> > > > The MAJOR number conforms to the major in semver.org. It increments on a
> > > > backwards incompatible change of the interface. It resets to 1 on a change of
> > > > BASE. The MAJOR number basically works the same between the current and
> > > > proposed versioning schemes.
> > > >
> > > > The MINOR number conforms to the minor in semver.org. It increments on a
> > > > backwards compatible change of the interface (new interfaces that are optional
> > > > to use). It will also increment on substantial new internal functionality that
> > > > doesn't affect the interface but should be called out to the user. It resets to
> > > > 0 on a change of MAJOR. The MINOR number in the current versioning scheme
> > > > increments on any backwards compatible change. The proposed versioning scheme
> > > > breaks this into the MINOR number just described and the PATCH number below.
> > > >
> > > > The PATCH number conforms to the patch in semver.org. It increments on a
> > > > backwards compatible internal change, usually a bug fix. It resets to 0 on a
> > > > change of MINOR.
> > >
> > > I like the idea of MAJOR.MINOR.PATCH following semver.org.
> > >
> > > I think if we remove the BASE out of picture and just use semver clear,
> > > but maybe it is just because I didn't quite understand BASE.
> > >
> > > >
> > > > The MAJOR.MINOR collectively define the interface version. Because the MINOR
> > > > may also increment on a substantial internal change, it doesn't always mark an
> > > > interface change, e.g. 4.5 and 4.6 may have identical interfaces. But the
> > > > determination of interface compatibility is unchanged, e.g. 4.6 is always
> > > > backwards compatible with 4.5.
> > > >
> > > > Each MAJOR.MINOR may continue to receive internal fixes along a branch even
> > > > after the main branch for that BASE has moved on to another MAJOR.MINOR.
> > > > Releases from these fix-only branches increment only the PATCH number on that
> > > > MAJOR.MINOR, and therefore remain semantically consistent with the main branch.
> > > > No change of BASE is therefore needed. Consider an example:
> > > >
> > > > v1.1.0.0   v1.1.0.1   v1.1.0.2   v1.1.1.0   v1.1.1.1
> > > > ----O----------O----------O----------O----------O    <-- main adopts v1.1.1.x
> > > >                            \
> > > >                             \
> > > >                              \
> > > >                               O----------O     <-- fixes for interface v1.1.0.x
> > > >                           v1.1.0.3   v1.1.0.4
> > >
> > > This approach is cool and more or less how Mesa handles their releases,
> > > except by the fact that their Major is the year and minor is the month.
> > >
> > > However, on the firmware side I have a concern because we are so far trying
> > > to make sure that we have 1-1 relationship on kernel-firmware version.
> > >
> > > But based on this view and what Anusha told me yesterday it seems
> > > that GuC is getting constant releases. With the constant patches we will
> > > soon explode linux-firmware.git repository size.
> > >
> > > But this maybe is something to be solved on linux-firmware side and we make
> > > sure that we clean up and remove firmware that were never released in any
> > > official Linux kernel. Anusha or Antonio, thoughts?
> > >
> > > Thanks,
> > > Rodrigo.
> > >
> >
> > I expect that i915 will still require a single version of firmware per platform
> > as it does today. This change should not impact that other than to require i915
> > to check 4 numbers instead of 2.
> >
> > It is true that firmware releases are made *internally* (from the firmware
> > team to the operating system teams) at a frequent rate. It is up to each OS
> > team to decide their own cadence for integrating and distributing those
> > firmware based on their unique situation. So the Linux team may filter these
> > releases and update the upstream much less frequently.
> >
> > > >
> > > > There is no need to change the BASE because the branching happened from the
> > > > last fix (v1.1.0.2) on the main branch prior to the change of interface
> > > > (v1.1.1.0). As long as only fixes are applied to v1.1.0.x, there is no risk of
> > > > version number clash. All of these release versions remain semantically
> > > > connected with one small caveat. If this set of release versions came
> > > > sequentially along a single branch, one could infer that the exact fixes in
> > > > v1.1.0.4 were inherited by v1.1.1.0. With this "hidden" branching, this may
> > > > not be true as in this example. One would need to review the v1.1.1.0 release
> > > > notes to check.
> > > >
> > > > Please provide any feedback on the proposed change.
> > > >
> > > > Thanks,
> > > > Jeff
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx



-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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Re: [RFC] GuC firmware versioning change

[Jeff McGee]

On Thu, Oct 18, 2018 at 11:57:06AM +0200, Daniel Vetter wrote:
> On Fri, Oct 12, 2018 at 11:45 PM Jeff McGee <jeff.mcgee@intel.com> wrote:
> >
> > On Fri, Oct 12, 2018 at 02:33:26PM -0700, Jeff McGee wrote:
> > > On Fri, Oct 12, 2018 at 01:51:46PM -0700, Rodrigo Vivi wrote:
> > > > On Fri, Oct 12, 2018 at 01:24:30PM -0700, Jeff McGee wrote:
> > > > > The GuC firmware team is proposing a change to the firmware versioning scheme.
> > > > > The goal is to more accurately track the firmware interface to help users
> > > > > manage dependencies on that interface. The proposed scheme is based on
> > > > > semver.org with some additions to handle branching.
> > > > >
> > > > > The proposed version number would have 4 fields: BASE.MAJOR.MINOR.PATCH.
> > > > > Contrast this with the 2 fields in the current version number: MAJOR.MINOR.
> > > > > Side note, the current firmware encodes a BRANCH and CLIENT number as well, but
> > > > > they have not been needed by i915. So a firmware released with the proposed
> > > > > scheme would be named <platform>_guc_ver<base>_<major>_<minor>_<patch>.bin
> > > > > (ex: skl_guc_ver1_5_4_7.bin) instead of the current
> > > > > <platform>_guc_ver<major>_<minor>.bin (ex: skl_guc_ver9_33.bin).
> > > > >
> > > > > The BASE number is an ID that is used to identify a set of releases in which
> > > > > the MAJOR.MINOR.PATCH semantics are consistent. In other words, two releases
> > > > > from the same BASE can be compared via their MAJOR.MINOR.PATCH to infer their
> > > > > relationship as described below. Two releases from a different BASE cannot be
> > > > > reliably compared. The BASE number facilitates arbitrary branching which can
> > > > > create duplicate and/or disconnected MAJOR.MINOR.PATCH versions. This type of
> > > > > branching is expected to be rare, and so BASE will rarely change. When a new
> > > > > BASE is created, the MAJOR.MINOR.PATCH reset to starting values.
> > > >
> > > > Could you please clarify a bit what BASE means?
> > > > What would be a different BASE?
> > > >
> > >
> > > The BASE number supports general branching that would cause version number
> > > conflicts. Branching for firmware releases is not desirable, but it is a
> > > practical reality. Therefore the versioning scheme must accomodate it. Let's
> > > say that a high-priority request is made to put specific updates on an old
> > > release that said customer is locked on. Those updates could include any sort
> > > of change including interface change. Then we have a sequence like below:
> > >
> > > v1.1.0.0   v1.1.0.1   v1.1.0.2   v1.1.0.3   v1.1.1.0
> > > ----O----------O----------O----------O----------O
> > >                            \
> > >                             \
> > >                              \
> > >                               O----------O
> > >                           v2.1.1.0   v2.1.1.1
> > >
> > > You can see that if we don't have a BASE number that changes from 1 to 2, then
> > > we end up with duplicated v1.1.0 along the different branches which are not the
> > > same. As I wrote, this should be a very rare scenario, but it can happen. Maybe
> > > upstream will always be supplied with releases from the "main" BASE, and you
> > > can ignore this field, but it needs to be there for other firmware
> > > distributions.
> 
> The way this is usually solved in semver is to not prepend a BASE, but
> postfix a branch-specific version, while keeping the mainline version
> unchanged. So
> 
> v2.1.1.0 becomes v1.1.0.1-branch1-0
> v2.1.1.1 becomes v1.1.0.1-branch1-1
> 
> With the rule that branches are explicitly unsorted (that's denoted by
> the - - around them, instead o using dots), so not comparable. Bonus
> points if you name the branch points by the customers (could be the
> product, or internal customer group or whatever) to make these names
> slightly more meaningful.
> 
I don't see any mention of branch handling on semver.org. It discusses using
hyphen for pre-release versions and plus for metadata. Any other references
you can share would be appreciated.

We can certainly use an approach like this, where the branch ID (changed from
BASE ID) is appended via the hyphen only if necessary. We would probably stick
with a simple numerical branch ID rather than a string, so that the full
version encoded in firmware is compact. We have 64 bits currently allocated
for version info in the CSS. We could define an enumeration in the interface
to name each ID more verbosely.

I'm still not clear on how the major.minor.patch should change in this model
when the first and subsequent releases from a branch are made. Your example
seems to indicate that major.minor.patch are locked, and each release for
the branch gets one incremented version at the end. I would prefer that the
major.minor.patch continue to evolve on the branch per normal convention, but
then the branch ID would indicate that there is no gauranteed relationship to
any major.minor.patch on another branch. So in below sequence the "1" branch
resets to v1.0.0 for first release, then next release is v1.1.0 if for example
a backwards compatible interface change is made, and so on. Does that seem
reasonable?

 v1.0.0     v1.0.1     v1.0.2     v1.0.3     v1.1.0
----O----------O----------O----------O----------O
                           \
                            \
                             \
                              O----------O
                          v1.0.0-1   v1.1.0-1

-Jeff

> Prefixing a BASE, with a dot, is very much not how it's done and very
> confusing. There's one thing debian does, it's prepending an EPOCH,
> which is used for e.g. C++ packages when the compiler abi changes. I
> think reading up on debian's rules would be good inspiration for this
> problem:
> 
> https://serverfault.com/questions/604541/debian-packages-version-convention
> 
> Cheers, Daniel
> 
> > > -Jeff
> > >
> >
> > Sorry, I misrepresented how to the numbers would change in the above example.
> > The change of BASE from 1 to 2 would reset MAJOR.MINOR.PATCH. So the sequence
> > should be v1.1.0.2 -> v2.1.0.0 -> v2.1.0.1 and so on.
> >
> > If we don't have BASE, the pure semver.org sequence would be:
> >
> >   v1.0.0     v1.0.1     v1.0.2     v1.0.3     v1.1.0
> > ----O----------O----------O----------O----------O
> >                            \
> >                             \
> >                              \
> >                               O----------O
> >                             v1.1.0     v1.1.1
> >
> > And so you see the duplication of version number.
> > - Jeff
> >
> > > > >
> > > > > The MAJOR number conforms to the major in semver.org. It increments on a
> > > > > backwards incompatible change of the interface. It resets to 1 on a change of
> > > > > BASE. The MAJOR number basically works the same between the current and
> > > > > proposed versioning schemes.
> > > > >
> > > > > The MINOR number conforms to the minor in semver.org. It increments on a
> > > > > backwards compatible change of the interface (new interfaces that are optional
> > > > > to use). It will also increment on substantial new internal functionality that
> > > > > doesn't affect the interface but should be called out to the user. It resets to
> > > > > 0 on a change of MAJOR. The MINOR number in the current versioning scheme
> > > > > increments on any backwards compatible change. The proposed versioning scheme
> > > > > breaks this into the MINOR number just described and the PATCH number below.
> > > > >
> > > > > The PATCH number conforms to the patch in semver.org. It increments on a
> > > > > backwards compatible internal change, usually a bug fix. It resets to 0 on a
> > > > > change of MINOR.
> > > >
> > > > I like the idea of MAJOR.MINOR.PATCH following semver.org.
> > > >
> > > > I think if we remove the BASE out of picture and just use semver clear,
> > > > but maybe it is just because I didn't quite understand BASE.
> > > >
> > > > >
> > > > > The MAJOR.MINOR collectively define the interface version. Because the MINOR
> > > > > may also increment on a substantial internal change, it doesn't always mark an
> > > > > interface change, e.g. 4.5 and 4.6 may have identical interfaces. But the
> > > > > determination of interface compatibility is unchanged, e.g. 4.6 is always
> > > > > backwards compatible with 4.5.
> > > > >
> > > > > Each MAJOR.MINOR may continue to receive internal fixes along a branch even
> > > > > after the main branch for that BASE has moved on to another MAJOR.MINOR.
> > > > > Releases from these fix-only branches increment only the PATCH number on that
> > > > > MAJOR.MINOR, and therefore remain semantically consistent with the main branch.
> > > > > No change of BASE is therefore needed. Consider an example:
> > > > >
> > > > > v1.1.0.0   v1.1.0.1   v1.1.0.2   v1.1.1.0   v1.1.1.1
> > > > > ----O----------O----------O----------O----------O    <-- main adopts v1.1.1.x
> > > > >                            \
> > > > >                             \
> > > > >                              \
> > > > >                               O----------O     <-- fixes for interface v1.1.0.x
> > > > >                           v1.1.0.3   v1.1.0.4
> > > >
> > > > This approach is cool and more or less how Mesa handles their releases,
> > > > except by the fact that their Major is the year and minor is the month.
> > > >
> > > > However, on the firmware side I have a concern because we are so far trying
> > > > to make sure that we have 1-1 relationship on kernel-firmware version.
> > > >
> > > > But based on this view and what Anusha told me yesterday it seems
> > > > that GuC is getting constant releases. With the constant patches we will
> > > > soon explode linux-firmware.git repository size.
> > > >
> > > > But this maybe is something to be solved on linux-firmware side and we make
> > > > sure that we clean up and remove firmware that were never released in any
> > > > official Linux kernel. Anusha or Antonio, thoughts?
> > > >
> > > > Thanks,
> > > > Rodrigo.
> > > >
> > >
> > > I expect that i915 will still require a single version of firmware per platform
> > > as it does today. This change should not impact that other than to require i915
> > > to check 4 numbers instead of 2.
> > >
> > > It is true that firmware releases are made *internally* (from the firmware
> > > team to the operating system teams) at a frequent rate. It is up to each OS
> > > team to decide their own cadence for integrating and distributing those
> > > firmware based on their unique situation. So the Linux team may filter these
> > > releases and update the upstream much less frequently.
> > >
> > > > >
> > > > > There is no need to change the BASE because the branching happened from the
> > > > > last fix (v1.1.0.2) on the main branch prior to the change of interface
> > > > > (v1.1.1.0). As long as only fixes are applied to v1.1.0.x, there is no risk of
> > > > > version number clash. All of these release versions remain semantically
> > > > > connected with one small caveat. If this set of release versions came
> > > > > sequentially along a single branch, one could infer that the exact fixes in
> > > > > v1.1.0.4 were inherited by v1.1.1.0. With this "hidden" branching, this may
> > > > > not be true as in this example. One would need to review the v1.1.1.0 release
> > > > > notes to check.
> > > > >
> > > > > Please provide any feedback on the proposed change.
> > > > >
> > > > > Thanks,
> > > > > Jeff
> > > _______________________________________________
> > > Intel-gfx mailing list
> > > Intel-gfx@lists.freedesktop.org
> > > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> 
> 
> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - http://blog.ffwll.ch
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

Re: [RFC] GuC firmware versioning change

[Rodrigo Vivi]

On Thu, Oct 18, 2018 at 10:32:37AM -0700, Jeff McGee wrote:
> On Thu, Oct 18, 2018 at 11:57:06AM +0200, Daniel Vetter wrote:
> > On Fri, Oct 12, 2018 at 11:45 PM Jeff McGee <jeff.mcgee@intel.com> wrote:
> > >
> > > On Fri, Oct 12, 2018 at 02:33:26PM -0700, Jeff McGee wrote:
> > > > On Fri, Oct 12, 2018 at 01:51:46PM -0700, Rodrigo Vivi wrote:
> > > > > On Fri, Oct 12, 2018 at 01:24:30PM -0700, Jeff McGee wrote:
> > > > > > The GuC firmware team is proposing a change to the firmware versioning scheme.
> > > > > > The goal is to more accurately track the firmware interface to help users
> > > > > > manage dependencies on that interface. The proposed scheme is based on
> > > > > > semver.org with some additions to handle branching.
> > > > > >
> > > > > > The proposed version number would have 4 fields: BASE.MAJOR.MINOR.PATCH.
> > > > > > Contrast this with the 2 fields in the current version number: MAJOR.MINOR.
> > > > > > Side note, the current firmware encodes a BRANCH and CLIENT number as well, but
> > > > > > they have not been needed by i915. So a firmware released with the proposed
> > > > > > scheme would be named <platform>_guc_ver<base>_<major>_<minor>_<patch>.bin
> > > > > > (ex: skl_guc_ver1_5_4_7.bin) instead of the current
> > > > > > <platform>_guc_ver<major>_<minor>.bin (ex: skl_guc_ver9_33.bin).
> > > > > >
> > > > > > The BASE number is an ID that is used to identify a set of releases in which
> > > > > > the MAJOR.MINOR.PATCH semantics are consistent. In other words, two releases
> > > > > > from the same BASE can be compared via their MAJOR.MINOR.PATCH to infer their
> > > > > > relationship as described below. Two releases from a different BASE cannot be
> > > > > > reliably compared. The BASE number facilitates arbitrary branching which can
> > > > > > create duplicate and/or disconnected MAJOR.MINOR.PATCH versions. This type of
> > > > > > branching is expected to be rare, and so BASE will rarely change. When a new
> > > > > > BASE is created, the MAJOR.MINOR.PATCH reset to starting values.
> > > > >
> > > > > Could you please clarify a bit what BASE means?
> > > > > What would be a different BASE?
> > > > >
> > > >
> > > > The BASE number supports general branching that would cause version number
> > > > conflicts. Branching for firmware releases is not desirable, but it is a
> > > > practical reality. Therefore the versioning scheme must accomodate it. Let's
> > > > say that a high-priority request is made to put specific updates on an old
> > > > release that said customer is locked on. Those updates could include any sort
> > > > of change including interface change. Then we have a sequence like below:
> > > >
> > > > v1.1.0.0   v1.1.0.1   v1.1.0.2   v1.1.0.3   v1.1.1.0
> > > > ----O----------O----------O----------O----------O
> > > >                            \
> > > >                             \
> > > >                              \
> > > >                               O----------O
> > > >                           v2.1.1.0   v2.1.1.1
> > > >
> > > > You can see that if we don't have a BASE number that changes from 1 to 2, then
> > > > we end up with duplicated v1.1.0 along the different branches which are not the
> > > > same. As I wrote, this should be a very rare scenario, but it can happen. Maybe
> > > > upstream will always be supplied with releases from the "main" BASE, and you
> > > > can ignore this field, but it needs to be there for other firmware
> > > > distributions.
> > 
> > The way this is usually solved in semver is to not prepend a BASE, but
> > postfix a branch-specific version, while keeping the mainline version
> > unchanged. So
> > 
> > v2.1.1.0 becomes v1.1.0.1-branch1-0
> > v2.1.1.1 becomes v1.1.0.1-branch1-1

+1. This would be much cleaner.


> > 
> > With the rule that branches are explicitly unsorted (that's denoted by
> > the - - around them, instead o using dots), so not comparable. Bonus
> > points if you name the branch points by the customers (could be the
> > product, or internal customer group or whatever) to make these names
> > slightly more meaningful.

+1 for meaningful names.

> > 
> I don't see any mention of branch handling on semver.org.

Also I don't see an extra field for base on semver.org.
So Daniel is showing how it is usually solved on many Linux distros
and packages without creating this complexity.

> It discusses using
> hyphen for pre-release versions and plus for metadata. Any other references
> you can share would be appreciated.
> 
> We can certainly use an approach like this, where the branch ID (changed from
> BASE ID) is appended via the hyphen only if necessary. We would probably stick
> with a simple numerical branch ID rather than a string,

so branch1, branch2... at least it gets clear for everyone
that this is the branch and not the mainline, while mainline keeps
the clean semver.

> so that the full
> version encoded in firmware is compact. We have 64 bits currently allocated
> for version info in the CSS. We could define an enumeration in the interface
> to name each ID more verbosely.

save one int for branch number. if 0 it is mainline and filename doesn't
need to have any string, otherwise -branch<int>.

> 
> I'm still not clear on how the major.minor.patch should change in this model
> when the first and subsequent releases from a branch are made. Your example
> seems to indicate that major.minor.patch are locked, and each release for
> the branch gets one incremented version at the end. I would prefer that the
> major.minor.patch continue to evolve on the branch per normal convention, but
> then the branch ID would indicate that there is no gauranteed relationship to
> any major.minor.patch on another branch. So in below sequence the "1" branch
> resets to v1.0.0 for first release, then next release is v1.1.0 if for example
> a backwards compatible interface change is made, and so on. Does that seem
> reasonable?
> 

If I was one of the users of branched versioning I'd like to know how
it compares with the mainline.

So if I recieve a v1.0.0.1 I would imediatelly assume this was derivated
from 1.0.0 instead of 1.0.2.

>  v1.0.0     v1.0.1     v1.0.2     v1.0.3     v1.1.0
> ----O----------O----------O----------O----------O
>                            \
>                             \
>                              \
>                               O----------O
>                           v1.0.0-1   v1.1.0-1

For the repensentation I thing that internally you can save only number
one, but when building final file name for distribution we should print
v1.0.0-branch1 ....  v1.1.0-branch1

or even better with meaningful strings instead of branch
as Daniel suggested.

maybe an external mapping table from branch numbers to customer strings?

Thanks,
Rodrigo.

> 
> -Jeff
> 
> > Prefixing a BASE, with a dot, is very much not how it's done and very
> > confusing. There's one thing debian does, it's prepending an EPOCH,
> > which is used for e.g. C++ packages when the compiler abi changes. I
> > think reading up on debian's rules would be good inspiration for this
> > problem:
> > 
> > https://serverfault.com/questions/604541/debian-packages-version-convention
> > 
> > Cheers, Daniel
> > 
> > > > -Jeff
> > > >
> > >
> > > Sorry, I misrepresented how to the numbers would change in the above example.
> > > The change of BASE from 1 to 2 would reset MAJOR.MINOR.PATCH. So the sequence
> > > should be v1.1.0.2 -> v2.1.0.0 -> v2.1.0.1 and so on.
> > >
> > > If we don't have BASE, the pure semver.org sequence would be:
> > >
> > >   v1.0.0     v1.0.1     v1.0.2     v1.0.3     v1.1.0
> > > ----O----------O----------O----------O----------O
> > >                            \
> > >                             \
> > >                              \
> > >                               O----------O
> > >                             v1.1.0     v1.1.1
> > >
> > > And so you see the duplication of version number.
> > > - Jeff
> > >
> > > > > >
> > > > > > The MAJOR number conforms to the major in semver.org. It increments on a
> > > > > > backwards incompatible change of the interface. It resets to 1 on a change of
> > > > > > BASE. The MAJOR number basically works the same between the current and
> > > > > > proposed versioning schemes.
> > > > > >
> > > > > > The MINOR number conforms to the minor in semver.org. It increments on a
> > > > > > backwards compatible change of the interface (new interfaces that are optional
> > > > > > to use). It will also increment on substantial new internal functionality that
> > > > > > doesn't affect the interface but should be called out to the user. It resets to
> > > > > > 0 on a change of MAJOR. The MINOR number in the current versioning scheme
> > > > > > increments on any backwards compatible change. The proposed versioning scheme
> > > > > > breaks this into the MINOR number just described and the PATCH number below.
> > > > > >
> > > > > > The PATCH number conforms to the patch in semver.org. It increments on a
> > > > > > backwards compatible internal change, usually a bug fix. It resets to 0 on a
> > > > > > change of MINOR.
> > > > >
> > > > > I like the idea of MAJOR.MINOR.PATCH following semver.org.
> > > > >
> > > > > I think if we remove the BASE out of picture and just use semver clear,
> > > > > but maybe it is just because I didn't quite understand BASE.
> > > > >
> > > > > >
> > > > > > The MAJOR.MINOR collectively define the interface version. Because the MINOR
> > > > > > may also increment on a substantial internal change, it doesn't always mark an
> > > > > > interface change, e.g. 4.5 and 4.6 may have identical interfaces. But the
> > > > > > determination of interface compatibility is unchanged, e.g. 4.6 is always
> > > > > > backwards compatible with 4.5.
> > > > > >
> > > > > > Each MAJOR.MINOR may continue to receive internal fixes along a branch even
> > > > > > after the main branch for that BASE has moved on to another MAJOR.MINOR.
> > > > > > Releases from these fix-only branches increment only the PATCH number on that
> > > > > > MAJOR.MINOR, and therefore remain semantically consistent with the main branch.
> > > > > > No change of BASE is therefore needed. Consider an example:
> > > > > >
> > > > > > v1.1.0.0   v1.1.0.1   v1.1.0.2   v1.1.1.0   v1.1.1.1
> > > > > > ----O----------O----------O----------O----------O    <-- main adopts v1.1.1.x
> > > > > >                            \
> > > > > >                             \
> > > > > >                              \
> > > > > >                               O----------O     <-- fixes for interface v1.1.0.x
> > > > > >                           v1.1.0.3   v1.1.0.4
> > > > >
> > > > > This approach is cool and more or less how Mesa handles their releases,
> > > > > except by the fact that their Major is the year and minor is the month.
> > > > >
> > > > > However, on the firmware side I have a concern because we are so far trying
> > > > > to make sure that we have 1-1 relationship on kernel-firmware version.
> > > > >
> > > > > But based on this view and what Anusha told me yesterday it seems
> > > > > that GuC is getting constant releases. With the constant patches we will
> > > > > soon explode linux-firmware.git repository size.
> > > > >
> > > > > But this maybe is something to be solved on linux-firmware side and we make
> > > > > sure that we clean up and remove firmware that were never released in any
> > > > > official Linux kernel. Anusha or Antonio, thoughts?
> > > > >
> > > > > Thanks,
> > > > > Rodrigo.
> > > > >
> > > >
> > > > I expect that i915 will still require a single version of firmware per platform
> > > > as it does today. This change should not impact that other than to require i915
> > > > to check 4 numbers instead of 2.
> > > >
> > > > It is true that firmware releases are made *internally* (from the firmware
> > > > team to the operating system teams) at a frequent rate. It is up to each OS
> > > > team to decide their own cadence for integrating and distributing those
> > > > firmware based on their unique situation. So the Linux team may filter these
> > > > releases and update the upstream much less frequently.
> > > >
> > > > > >
> > > > > > There is no need to change the BASE because the branching happened from the
> > > > > > last fix (v1.1.0.2) on the main branch prior to the change of interface
> > > > > > (v1.1.1.0). As long as only fixes are applied to v1.1.0.x, there is no risk of
> > > > > > version number clash. All of these release versions remain semantically
> > > > > > connected with one small caveat. If this set of release versions came
> > > > > > sequentially along a single branch, one could infer that the exact fixes in
> > > > > > v1.1.0.4 were inherited by v1.1.1.0. With this "hidden" branching, this may
> > > > > > not be true as in this example. One would need to review the v1.1.1.0 release
> > > > > > notes to check.
> > > > > >
> > > > > > Please provide any feedback on the proposed change.
> > > > > >
> > > > > > Thanks,
> > > > > > Jeff
> > > > _______________________________________________
> > > > Intel-gfx mailing list
> > > > Intel-gfx@lists.freedesktop.org
> > > > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> > > _______________________________________________
> > > Intel-gfx mailing list
> > > Intel-gfx@lists.freedesktop.org
> > > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> > 
> > 
> > 
> > -- 
> > Daniel Vetter
> > Software Engineer, Intel Corporation
> > +41 (0) 79 365 57 48 - http://blog.ffwll.ch
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

Re: [RFC] GuC firmware versioning change

[Jeff McGee]

On Thu, Oct 18, 2018 at 11:12:21AM -0700, Rodrigo Vivi wrote:
> On Thu, Oct 18, 2018 at 10:32:37AM -0700, Jeff McGee wrote:
> > On Thu, Oct 18, 2018 at 11:57:06AM +0200, Daniel Vetter wrote:
> > > On Fri, Oct 12, 2018 at 11:45 PM Jeff McGee <jeff.mcgee@intel.com> wrote:
> > > >
> > > > On Fri, Oct 12, 2018 at 02:33:26PM -0700, Jeff McGee wrote:
> > > > > On Fri, Oct 12, 2018 at 01:51:46PM -0700, Rodrigo Vivi wrote:
> > > > > > On Fri, Oct 12, 2018 at 01:24:30PM -0700, Jeff McGee wrote:
> > > > > > > The GuC firmware team is proposing a change to the firmware versioning scheme.
> > > > > > > The goal is to more accurately track the firmware interface to help users
> > > > > > > manage dependencies on that interface. The proposed scheme is based on
> > > > > > > semver.org with some additions to handle branching.
> > > > > > >
> > > > > > > The proposed version number would have 4 fields: BASE.MAJOR.MINOR.PATCH.
> > > > > > > Contrast this with the 2 fields in the current version number: MAJOR.MINOR.
> > > > > > > Side note, the current firmware encodes a BRANCH and CLIENT number as well, but
> > > > > > > they have not been needed by i915. So a firmware released with the proposed
> > > > > > > scheme would be named <platform>_guc_ver<base>_<major>_<minor>_<patch>.bin
> > > > > > > (ex: skl_guc_ver1_5_4_7.bin) instead of the current
> > > > > > > <platform>_guc_ver<major>_<minor>.bin (ex: skl_guc_ver9_33.bin).
> > > > > > >
> > > > > > > The BASE number is an ID that is used to identify a set of releases in which
> > > > > > > the MAJOR.MINOR.PATCH semantics are consistent. In other words, two releases
> > > > > > > from the same BASE can be compared via their MAJOR.MINOR.PATCH to infer their
> > > > > > > relationship as described below. Two releases from a different BASE cannot be
> > > > > > > reliably compared. The BASE number facilitates arbitrary branching which can
> > > > > > > create duplicate and/or disconnected MAJOR.MINOR.PATCH versions. This type of
> > > > > > > branching is expected to be rare, and so BASE will rarely change. When a new
> > > > > > > BASE is created, the MAJOR.MINOR.PATCH reset to starting values.
> > > > > >
> > > > > > Could you please clarify a bit what BASE means?
> > > > > > What would be a different BASE?
> > > > > >
> > > > >
> > > > > The BASE number supports general branching that would cause version number
> > > > > conflicts. Branching for firmware releases is not desirable, but it is a
> > > > > practical reality. Therefore the versioning scheme must accomodate it. Let's
> > > > > say that a high-priority request is made to put specific updates on an old
> > > > > release that said customer is locked on. Those updates could include any sort
> > > > > of change including interface change. Then we have a sequence like below:
> > > > >
> > > > > v1.1.0.0   v1.1.0.1   v1.1.0.2   v1.1.0.3   v1.1.1.0
> > > > > ----O----------O----------O----------O----------O
> > > > >                            \
> > > > >                             \
> > > > >                              \
> > > > >                               O----------O
> > > > >                           v2.1.1.0   v2.1.1.1
> > > > >
> > > > > You can see that if we don't have a BASE number that changes from 1 to 2, then
> > > > > we end up with duplicated v1.1.0 along the different branches which are not the
> > > > > same. As I wrote, this should be a very rare scenario, but it can happen. Maybe
> > > > > upstream will always be supplied with releases from the "main" BASE, and you
> > > > > can ignore this field, but it needs to be there for other firmware
> > > > > distributions.
> > > 
> > > The way this is usually solved in semver is to not prepend a BASE, but
> > > postfix a branch-specific version, while keeping the mainline version
> > > unchanged. So
> > > 
> > > v2.1.1.0 becomes v1.1.0.1-branch1-0
> > > v2.1.1.1 becomes v1.1.0.1-branch1-1
> 
> +1. This would be much cleaner.
> 
> 
> > > 
> > > With the rule that branches are explicitly unsorted (that's denoted by
> > > the - - around them, instead o using dots), so not comparable. Bonus
> > > points if you name the branch points by the customers (could be the
> > > product, or internal customer group or whatever) to make these names
> > > slightly more meaningful.
> 
> +1 for meaningful names.
> 
> > > 
> > I don't see any mention of branch handling on semver.org.
> 
> Also I don't see an extra field for base on semver.org.
> So Daniel is showing how it is usually solved on many Linux distros
> and packages without creating this complexity.
> 
> > It discusses using
> > hyphen for pre-release versions and plus for metadata. Any other references
> > you can share would be appreciated.
> > 
> > We can certainly use an approach like this, where the branch ID (changed from
> > BASE ID) is appended via the hyphen only if necessary. We would probably stick
> > with a simple numerical branch ID rather than a string,
> 
> so branch1, branch2... at least it gets clear for everyone
> that this is the branch and not the mainline, while mainline keeps
> the clean semver.
> 
> > so that the full
> > version encoded in firmware is compact. We have 64 bits currently allocated
> > for version info in the CSS. We could define an enumeration in the interface
> > to name each ID more verbosely.
> 
> save one int for branch number. if 0 it is mainline and filename doesn't
> need to have any string, otherwise -branch<int>.
> 
> > 
> > I'm still not clear on how the major.minor.patch should change in this model
> > when the first and subsequent releases from a branch are made. Your example
> > seems to indicate that major.minor.patch are locked, and each release for
> > the branch gets one incremented version at the end. I would prefer that the
> > major.minor.patch continue to evolve on the branch per normal convention, but
> > then the branch ID would indicate that there is no gauranteed relationship to
> > any major.minor.patch on another branch. So in below sequence the "1" branch
> > resets to v1.0.0 for first release, then next release is v1.1.0 if for example
> > a backwards compatible interface change is made, and so on. Does that seem
> > reasonable?
> > 
> 
> If I was one of the users of branched versioning I'd like to know how
> it compares with the mainline.
> 
> So if I recieve a v1.0.0.1 I would imediatelly assume this was derivated
> from 1.0.0 instead of 1.0.2.
> 

So are you saying that when branching from mainline v1.0.2, the first release
should use v1.0.2-branch1? But what would the subsequent versions use? If I
lock the v1.0.2 portion to preserve branch-off point, I will need a 5th field
just to number the releases from this branch, e.g. v1.0.2-branch1-0,
v1.0.2-branch1-1, etc. I guess that is what Daniel suggested. But if the branch
is long-lived, I've now lost visibility into what sort of changes (interface or
internal) are going on. I guess that's the trade-off.

> >  v1.0.0     v1.0.1     v1.0.2     v1.0.3     v1.1.0
> > ----O----------O----------O----------O----------O
> >                            \
> >                             \
> >                              \
> >                               O----------O
> >                           v1.0.0-1   v1.1.0-1
> 
> For the repensentation I thing that internally you can save only number
> one, but when building final file name for distribution we should print
> v1.0.0-branch1 ....  v1.1.0-branch1
> 
> or even better with meaningful strings instead of branch
> as Daniel suggested.
> 
> maybe an external mapping table from branch numbers to customer strings?
> 

Agreed. The convention for naming the firmware file from the 4 basic numeric
fields is completely up to the OS team. So 3.4.1-3, 3.4.1-branch3, or
3.4.1-customerX (where customerX maps to branch id 3 through some table that
driver knows about) are all valid options. I think the mapping table should be
incorporated into the public interface spec in some fashion.
-Jeff

> Thanks,
> Rodrigo.
> 
> > 
> > -Jeff
> > 
> > > Prefixing a BASE, with a dot, is very much not how it's done and very
> > > confusing. There's one thing debian does, it's prepending an EPOCH,
> > > which is used for e.g. C++ packages when the compiler abi changes. I
> > > think reading up on debian's rules would be good inspiration for this
> > > problem:
> > > 
> > > https://serverfault.com/questions/604541/debian-packages-version-convention
> > > 
> > > Cheers, Daniel
> > > 
> > > > > -Jeff
> > > > >
> > > >
> > > > Sorry, I misrepresented how to the numbers would change in the above example.
> > > > The change of BASE from 1 to 2 would reset MAJOR.MINOR.PATCH. So the sequence
> > > > should be v1.1.0.2 -> v2.1.0.0 -> v2.1.0.1 and so on.
> > > >
> > > > If we don't have BASE, the pure semver.org sequence would be:
> > > >
> > > >   v1.0.0     v1.0.1     v1.0.2     v1.0.3     v1.1.0
> > > > ----O----------O----------O----------O----------O
> > > >                            \
> > > >                             \
> > > >                              \
> > > >                               O----------O
> > > >                             v1.1.0     v1.1.1
> > > >
> > > > And so you see the duplication of version number.
> > > > - Jeff
> > > >
> > > > > > >
> > > > > > > The MAJOR number conforms to the major in semver.org. It increments on a
> > > > > > > backwards incompatible change of the interface. It resets to 1 on a change of
> > > > > > > BASE. The MAJOR number basically works the same between the current and
> > > > > > > proposed versioning schemes.
> > > > > > >
> > > > > > > The MINOR number conforms to the minor in semver.org. It increments on a
> > > > > > > backwards compatible change of the interface (new interfaces that are optional
> > > > > > > to use). It will also increment on substantial new internal functionality that
> > > > > > > doesn't affect the interface but should be called out to the user. It resets to
> > > > > > > 0 on a change of MAJOR. The MINOR number in the current versioning scheme
> > > > > > > increments on any backwards compatible change. The proposed versioning scheme
> > > > > > > breaks this into the MINOR number just described and the PATCH number below.
> > > > > > >
> > > > > > > The PATCH number conforms to the patch in semver.org. It increments on a
> > > > > > > backwards compatible internal change, usually a bug fix. It resets to 0 on a
> > > > > > > change of MINOR.
> > > > > >
> > > > > > I like the idea of MAJOR.MINOR.PATCH following semver.org.
> > > > > >
> > > > > > I think if we remove the BASE out of picture and just use semver clear,
> > > > > > but maybe it is just because I didn't quite understand BASE.
> > > > > >
> > > > > > >
> > > > > > > The MAJOR.MINOR collectively define the interface version. Because the MINOR
> > > > > > > may also increment on a substantial internal change, it doesn't always mark an
> > > > > > > interface change, e.g. 4.5 and 4.6 may have identical interfaces. But the
> > > > > > > determination of interface compatibility is unchanged, e.g. 4.6 is always
> > > > > > > backwards compatible with 4.5.
> > > > > > >
> > > > > > > Each MAJOR.MINOR may continue to receive internal fixes along a branch even
> > > > > > > after the main branch for that BASE has moved on to another MAJOR.MINOR.
> > > > > > > Releases from these fix-only branches increment only the PATCH number on that
> > > > > > > MAJOR.MINOR, and therefore remain semantically consistent with the main branch.
> > > > > > > No change of BASE is therefore needed. Consider an example:
> > > > > > >
> > > > > > > v1.1.0.0   v1.1.0.1   v1.1.0.2   v1.1.1.0   v1.1.1.1
> > > > > > > ----O----------O----------O----------O----------O    <-- main adopts v1.1.1.x
> > > > > > >                            \
> > > > > > >                             \
> > > > > > >                              \
> > > > > > >                               O----------O     <-- fixes for interface v1.1.0.x
> > > > > > >                           v1.1.0.3   v1.1.0.4
> > > > > >
> > > > > > This approach is cool and more or less how Mesa handles their releases,
> > > > > > except by the fact that their Major is the year and minor is the month.
> > > > > >
> > > > > > However, on the firmware side I have a concern because we are so far trying
> > > > > > to make sure that we have 1-1 relationship on kernel-firmware version.
> > > > > >
> > > > > > But based on this view and what Anusha told me yesterday it seems
> > > > > > that GuC is getting constant releases. With the constant patches we will
> > > > > > soon explode linux-firmware.git repository size.
> > > > > >
> > > > > > But this maybe is something to be solved on linux-firmware side and we make
> > > > > > sure that we clean up and remove firmware that were never released in any
> > > > > > official Linux kernel. Anusha or Antonio, thoughts?
> > > > > >
> > > > > > Thanks,
> > > > > > Rodrigo.
> > > > > >
> > > > >
> > > > > I expect that i915 will still require a single version of firmware per platform
> > > > > as it does today. This change should not impact that other than to require i915
> > > > > to check 4 numbers instead of 2.
> > > > >
> > > > > It is true that firmware releases are made *internally* (from the firmware
> > > > > team to the operating system teams) at a frequent rate. It is up to each OS
> > > > > team to decide their own cadence for integrating and distributing those
> > > > > firmware based on their unique situation. So the Linux team may filter these
> > > > > releases and update the upstream much less frequently.
> > > > >
> > > > > > >
> > > > > > > There is no need to change the BASE because the branching happened from the
> > > > > > > last fix (v1.1.0.2) on the main branch prior to the change of interface
> > > > > > > (v1.1.1.0). As long as only fixes are applied to v1.1.0.x, there is no risk of
> > > > > > > version number clash. All of these release versions remain semantically
> > > > > > > connected with one small caveat. If this set of release versions came
> > > > > > > sequentially along a single branch, one could infer that the exact fixes in
> > > > > > > v1.1.0.4 were inherited by v1.1.1.0. With this "hidden" branching, this may
> > > > > > > not be true as in this example. One would need to review the v1.1.1.0 release
> > > > > > > notes to check.
> > > > > > >
> > > > > > > Please provide any feedback on the proposed change.
> > > > > > >
> > > > > > > Thanks,
> > > > > > > Jeff
> > > > > _______________________________________________
> > > > > Intel-gfx mailing list
> > > > > Intel-gfx@lists.freedesktop.org
> > > > > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> > > > _______________________________________________
> > > > Intel-gfx mailing list
> > > > Intel-gfx@lists.freedesktop.org
> > > > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> > > 
> > > 
> > > 
> > > -- 
> > > Daniel Vetter
> > > Software Engineer, Intel Corporation
> > > +41 (0) 79 365 57 48 - http://blog.ffwll.ch
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

Re: [RFC] GuC firmware versioning change

[Daniel Vetter]

On Thu, Oct 18, 2018 at 03:48:04PM -0700, Jeff McGee wrote:
> On Thu, Oct 18, 2018 at 11:12:21AM -0700, Rodrigo Vivi wrote:
> > On Thu, Oct 18, 2018 at 10:32:37AM -0700, Jeff McGee wrote:
> > > On Thu, Oct 18, 2018 at 11:57:06AM +0200, Daniel Vetter wrote:
> > > > On Fri, Oct 12, 2018 at 11:45 PM Jeff McGee <jeff.mcgee@intel.com> wrote:
> > > > >
> > > > > On Fri, Oct 12, 2018 at 02:33:26PM -0700, Jeff McGee wrote:
> > > > > > On Fri, Oct 12, 2018 at 01:51:46PM -0700, Rodrigo Vivi wrote:
> > > > > > > On Fri, Oct 12, 2018 at 01:24:30PM -0700, Jeff McGee wrote:
> > > > > > > > The GuC firmware team is proposing a change to the firmware versioning scheme.
> > > > > > > > The goal is to more accurately track the firmware interface to help users
> > > > > > > > manage dependencies on that interface. The proposed scheme is based on
> > > > > > > > semver.org with some additions to handle branching.
> > > > > > > >
> > > > > > > > The proposed version number would have 4 fields: BASE.MAJOR.MINOR.PATCH.
> > > > > > > > Contrast this with the 2 fields in the current version number: MAJOR.MINOR.
> > > > > > > > Side note, the current firmware encodes a BRANCH and CLIENT number as well, but
> > > > > > > > they have not been needed by i915. So a firmware released with the proposed
> > > > > > > > scheme would be named <platform>_guc_ver<base>_<major>_<minor>_<patch>.bin
> > > > > > > > (ex: skl_guc_ver1_5_4_7.bin) instead of the current
> > > > > > > > <platform>_guc_ver<major>_<minor>.bin (ex: skl_guc_ver9_33.bin).
> > > > > > > >
> > > > > > > > The BASE number is an ID that is used to identify a set of releases in which
> > > > > > > > the MAJOR.MINOR.PATCH semantics are consistent. In other words, two releases
> > > > > > > > from the same BASE can be compared via their MAJOR.MINOR.PATCH to infer their
> > > > > > > > relationship as described below. Two releases from a different BASE cannot be
> > > > > > > > reliably compared. The BASE number facilitates arbitrary branching which can
> > > > > > > > create duplicate and/or disconnected MAJOR.MINOR.PATCH versions. This type of
> > > > > > > > branching is expected to be rare, and so BASE will rarely change. When a new
> > > > > > > > BASE is created, the MAJOR.MINOR.PATCH reset to starting values.
> > > > > > >
> > > > > > > Could you please clarify a bit what BASE means?
> > > > > > > What would be a different BASE?
> > > > > > >
> > > > > >
> > > > > > The BASE number supports general branching that would cause version number
> > > > > > conflicts. Branching for firmware releases is not desirable, but it is a
> > > > > > practical reality. Therefore the versioning scheme must accomodate it. Let's
> > > > > > say that a high-priority request is made to put specific updates on an old
> > > > > > release that said customer is locked on. Those updates could include any sort
> > > > > > of change including interface change. Then we have a sequence like below:
> > > > > >
> > > > > > v1.1.0.0   v1.1.0.1   v1.1.0.2   v1.1.0.3   v1.1.1.0
> > > > > > ----O----------O----------O----------O----------O
> > > > > >                            \
> > > > > >                             \
> > > > > >                              \
> > > > > >                               O----------O
> > > > > >                           v2.1.1.0   v2.1.1.1
> > > > > >
> > > > > > You can see that if we don't have a BASE number that changes from 1 to 2, then
> > > > > > we end up with duplicated v1.1.0 along the different branches which are not the
> > > > > > same. As I wrote, this should be a very rare scenario, but it can happen. Maybe
> > > > > > upstream will always be supplied with releases from the "main" BASE, and you
> > > > > > can ignore this field, but it needs to be there for other firmware
> > > > > > distributions.
> > > > 
> > > > The way this is usually solved in semver is to not prepend a BASE, but
> > > > postfix a branch-specific version, while keeping the mainline version
> > > > unchanged. So
> > > > 
> > > > v2.1.1.0 becomes v1.1.0.1-branch1-0
> > > > v2.1.1.1 becomes v1.1.0.1-branch1-1
> > 
> > +1. This would be much cleaner.
> > 
> > 
> > > > 
> > > > With the rule that branches are explicitly unsorted (that's denoted by
> > > > the - - around them, instead o using dots), so not comparable. Bonus
> > > > points if you name the branch points by the customers (could be the
> > > > product, or internal customer group or whatever) to make these names
> > > > slightly more meaningful.
> > 
> > +1 for meaningful names.
> > 
> > > > 
> > > I don't see any mention of branch handling on semver.org.
> > 
> > Also I don't see an extra field for base on semver.org.
> > So Daniel is showing how it is usually solved on many Linux distros
> > and packages without creating this complexity.
> > 
> > > It discusses using
> > > hyphen for pre-release versions and plus for metadata. Any other references
> > > you can share would be appreciated.
> > > 
> > > We can certainly use an approach like this, where the branch ID (changed from
> > > BASE ID) is appended via the hyphen only if necessary. We would probably stick
> > > with a simple numerical branch ID rather than a string,
> > 
> > so branch1, branch2... at least it gets clear for everyone
> > that this is the branch and not the mainline, while mainline keeps
> > the clean semver.
> > 
> > > so that the full
> > > version encoded in firmware is compact. We have 64 bits currently allocated
> > > for version info in the CSS. We could define an enumeration in the interface
> > > to name each ID more verbosely.
> > 
> > save one int for branch number. if 0 it is mainline and filename doesn't
> > need to have any string, otherwise -branch<int>.
> > 
> > > 
> > > I'm still not clear on how the major.minor.patch should change in this model
> > > when the first and subsequent releases from a branch are made. Your example
> > > seems to indicate that major.minor.patch are locked, and each release for
> > > the branch gets one incremented version at the end. I would prefer that the
> > > major.minor.patch continue to evolve on the branch per normal convention, but
> > > then the branch ID would indicate that there is no gauranteed relationship to
> > > any major.minor.patch on another branch. So in below sequence the "1" branch
> > > resets to v1.0.0 for first release, then next release is v1.1.0 if for example
> > > a backwards compatible interface change is made, and so on. Does that seem
> > > reasonable?
> > > 
> > 
> > If I was one of the users of branched versioning I'd like to know how
> > it compares with the mainline.
> > 
> > So if I recieve a v1.0.0.1 I would imediatelly assume this was derivated
> > from 1.0.0 instead of 1.0.2.
> > 
> 
> So are you saying that when branching from mainline v1.0.2, the first release
> should use v1.0.2-branch1? But what would the subsequent versions use? If I
> lock the v1.0.2 portion to preserve branch-off point, I will need a 5th field
> just to number the releases from this branch, e.g. v1.0.2-branch1-0,
> v1.0.2-branch1-1, etc. I guess that is what Daniel suggested. But if the branch
> is long-lived, I've now lost visibility into what sort of changes (interface or
> internal) are going on. I guess that's the trade-off.


Yeah, the debian version number here doesn't work if you start doing abi
changes in your branch. If that's what you want to do, then semver is
really not possible, since semver assumes there's only one branch where
abi changes happen.

And the epoch: prefix that e.g. debian uses is also not for branches.

> > >  v1.0.0     v1.0.1     v1.0.2     v1.0.3     v1.1.0
> > > ----O----------O----------O----------O----------O
> > >                            \
> > >                             \
> > >                              \
> > >                               O----------O
> > >                           v1.0.0-1   v1.1.0-1
> > 
> > For the repensentation I thing that internally you can save only number
> > one, but when building final file name for distribution we should print
> > v1.0.0-branch1 ....  v1.1.0-branch1
> > 
> > or even better with meaningful strings instead of branch
> > as Daniel suggested.
> > 
> > maybe an external mapping table from branch numbers to customer strings?
> > 
> 
> Agreed. The convention for naming the firmware file from the 4 basic numeric
> fields is completely up to the OS team. So 3.4.1-3, 3.4.1-branch3, or
> 3.4.1-customerX (where customerX maps to branch id 3 through some table that
> driver knows about) are all valid options. I think the mapping table should be
> incorporated into the public interface spec in some fashion.

So from a practical point of view, do we ever expect to support anything
else but the main branch in upstream?

If that's the case then I think your BASE thing is ok, and we just
hard-code that in upstream to a fixed value. For anything else the
customer both needs a custom guc fw, and a custom i915.ko.

This is all assuming that you actually want to do abi changes in these
branches, which really doesn't sound like a good idea to me. If it's just
to denote fully compatible releases with a bugfix, branch of from some
other release, then adding more numbers at the end is the way to go (and
stay within usual versioning semantics). That's the v1.0.0-1 above.

Cheers, Daniel

> -Jeff
> 
> > Thanks,
> > Rodrigo.
> > 
> > > 
> > > -Jeff
> > > 
> > > > Prefixing a BASE, with a dot, is very much not how it's done and very
> > > > confusing. There's one thing debian does, it's prepending an EPOCH,
> > > > which is used for e.g. C++ packages when the compiler abi changes. I
> > > > think reading up on debian's rules would be good inspiration for this
> > > > problem:
> > > > 
> > > > https://serverfault.com/questions/604541/debian-packages-version-convention
> > > > 
> > > > Cheers, Daniel
> > > > 
> > > > > > -Jeff
> > > > > >
> > > > >
> > > > > Sorry, I misrepresented how to the numbers would change in the above example.
> > > > > The change of BASE from 1 to 2 would reset MAJOR.MINOR.PATCH. So the sequence
> > > > > should be v1.1.0.2 -> v2.1.0.0 -> v2.1.0.1 and so on.
> > > > >
> > > > > If we don't have BASE, the pure semver.org sequence would be:
> > > > >
> > > > >   v1.0.0     v1.0.1     v1.0.2     v1.0.3     v1.1.0
> > > > > ----O----------O----------O----------O----------O
> > > > >                            \
> > > > >                             \
> > > > >                              \
> > > > >                               O----------O
> > > > >                             v1.1.0     v1.1.1
> > > > >
> > > > > And so you see the duplication of version number.
> > > > > - Jeff
> > > > >
> > > > > > > >
> > > > > > > > The MAJOR number conforms to the major in semver.org. It increments on a
> > > > > > > > backwards incompatible change of the interface. It resets to 1 on a change of
> > > > > > > > BASE. The MAJOR number basically works the same between the current and
> > > > > > > > proposed versioning schemes.
> > > > > > > >
> > > > > > > > The MINOR number conforms to the minor in semver.org. It increments on a
> > > > > > > > backwards compatible change of the interface (new interfaces that are optional
> > > > > > > > to use). It will also increment on substantial new internal functionality that
> > > > > > > > doesn't affect the interface but should be called out to the user. It resets to
> > > > > > > > 0 on a change of MAJOR. The MINOR number in the current versioning scheme
> > > > > > > > increments on any backwards compatible change. The proposed versioning scheme
> > > > > > > > breaks this into the MINOR number just described and the PATCH number below.
> > > > > > > >
> > > > > > > > The PATCH number conforms to the patch in semver.org. It increments on a
> > > > > > > > backwards compatible internal change, usually a bug fix. It resets to 0 on a
> > > > > > > > change of MINOR.
> > > > > > >
> > > > > > > I like the idea of MAJOR.MINOR.PATCH following semver.org.
> > > > > > >
> > > > > > > I think if we remove the BASE out of picture and just use semver clear,
> > > > > > > but maybe it is just because I didn't quite understand BASE.
> > > > > > >
> > > > > > > >
> > > > > > > > The MAJOR.MINOR collectively define the interface version. Because the MINOR
> > > > > > > > may also increment on a substantial internal change, it doesn't always mark an
> > > > > > > > interface change, e.g. 4.5 and 4.6 may have identical interfaces. But the
> > > > > > > > determination of interface compatibility is unchanged, e.g. 4.6 is always
> > > > > > > > backwards compatible with 4.5.
> > > > > > > >
> > > > > > > > Each MAJOR.MINOR may continue to receive internal fixes along a branch even
> > > > > > > > after the main branch for that BASE has moved on to another MAJOR.MINOR.
> > > > > > > > Releases from these fix-only branches increment only the PATCH number on that
> > > > > > > > MAJOR.MINOR, and therefore remain semantically consistent with the main branch.
> > > > > > > > No change of BASE is therefore needed. Consider an example:
> > > > > > > >
> > > > > > > > v1.1.0.0   v1.1.0.1   v1.1.0.2   v1.1.1.0   v1.1.1.1
> > > > > > > > ----O----------O----------O----------O----------O    <-- main adopts v1.1.1.x
> > > > > > > >                            \
> > > > > > > >                             \
> > > > > > > >                              \
> > > > > > > >                               O----------O     <-- fixes for interface v1.1.0.x
> > > > > > > >                           v1.1.0.3   v1.1.0.4
> > > > > > >
> > > > > > > This approach is cool and more or less how Mesa handles their releases,
> > > > > > > except by the fact that their Major is the year and minor is the month.
> > > > > > >
> > > > > > > However, on the firmware side I have a concern because we are so far trying
> > > > > > > to make sure that we have 1-1 relationship on kernel-firmware version.
> > > > > > >
> > > > > > > But based on this view and what Anusha told me yesterday it seems
> > > > > > > that GuC is getting constant releases. With the constant patches we will
> > > > > > > soon explode linux-firmware.git repository size.
> > > > > > >
> > > > > > > But this maybe is something to be solved on linux-firmware side and we make
> > > > > > > sure that we clean up and remove firmware that were never released in any
> > > > > > > official Linux kernel. Anusha or Antonio, thoughts?
> > > > > > >
> > > > > > > Thanks,
> > > > > > > Rodrigo.
> > > > > > >
> > > > > >
> > > > > > I expect that i915 will still require a single version of firmware per platform
> > > > > > as it does today. This change should not impact that other than to require i915
> > > > > > to check 4 numbers instead of 2.
> > > > > >
> > > > > > It is true that firmware releases are made *internally* (from the firmware
> > > > > > team to the operating system teams) at a frequent rate. It is up to each OS
> > > > > > team to decide their own cadence for integrating and distributing those
> > > > > > firmware based on their unique situation. So the Linux team may filter these
> > > > > > releases and update the upstream much less frequently.
> > > > > >
> > > > > > > >
> > > > > > > > There is no need to change the BASE because the branching happened from the
> > > > > > > > last fix (v1.1.0.2) on the main branch prior to the change of interface
> > > > > > > > (v1.1.1.0). As long as only fixes are applied to v1.1.0.x, there is no risk of
> > > > > > > > version number clash. All of these release versions remain semantically
> > > > > > > > connected with one small caveat. If this set of release versions came
> > > > > > > > sequentially along a single branch, one could infer that the exact fixes in
> > > > > > > > v1.1.0.4 were inherited by v1.1.1.0. With this "hidden" branching, this may
> > > > > > > > not be true as in this example. One would need to review the v1.1.1.0 release
> > > > > > > > notes to check.
> > > > > > > >
> > > > > > > > Please provide any feedback on the proposed change.
> > > > > > > >
> > > > > > > > Thanks,
> > > > > > > > Jeff
> > > > > > _______________________________________________
> > > > > > Intel-gfx mailing list
> > > > > > Intel-gfx@lists.freedesktop.org
> > > > > > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> > > > > _______________________________________________
> > > > > Intel-gfx mailing list
> > > > > Intel-gfx@lists.freedesktop.org
> > > > > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> > > > 
> > > > 
> > > > 
> > > > -- 
> > > > Daniel Vetter
> > > > Software Engineer, Intel Corporation
> > > > +41 (0) 79 365 57 48 - http://blog.ffwll.ch

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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Re: [RFC] GuC firmware versioning change

[Srivatsa, Anusha]

>-----Original Message-----
>From: Mcgee, Jeff
>Sent: Friday, October 12, 2018 2:33 PM
>To: Vivi, Rodrigo <rodrigo.vivi@intel.com>
>Cc: intel-gfx@lists.freedesktop.org; Srivatsa, Anusha
><anusha.srivatsa@intel.com>; Spotswood, John A
><john.a.spotswood@intel.com>; joonas.lahtinen@linux.intel.com
>Subject: Re: [RFC] GuC firmware versioning change
>
>On Fri, Oct 12, 2018 at 01:51:46PM -0700, Rodrigo Vivi wrote:
>> On Fri, Oct 12, 2018 at 01:24:30PM -0700, Jeff McGee wrote:
>> > The GuC firmware team is proposing a change to the firmware versioning
>scheme.
>> > The goal is to more accurately track the firmware interface to help
>> > users manage dependencies on that interface. The proposed scheme is
>> > based on semver.org with some additions to handle branching.
>> >
>> > The proposed version number would have 4 fields:
>BASE.MAJOR.MINOR.PATCH.
>> > Contrast this with the 2 fields in the current version number: MAJOR.MINOR.
>> > Side note, the current firmware encodes a BRANCH and CLIENT number
>> > as well, but they have not been needed by i915. So a firmware
>> > released with the proposed scheme would be named
>> > <platform>_guc_ver<base>_<major>_<minor>_<patch>.bin
>> > (ex: skl_guc_ver1_5_4_7.bin) instead of the current
>> > <platform>_guc_ver<major>_<minor>.bin (ex: skl_guc_ver9_33.bin).
>> >
>> > The BASE number is an ID that is used to identify a set of releases
>> > in which the MAJOR.MINOR.PATCH semantics are consistent. In other
>> > words, two releases from the same BASE can be compared via their
>> > MAJOR.MINOR.PATCH to infer their relationship as described below.
>> > Two releases from a different BASE cannot be reliably compared. The
>> > BASE number facilitates arbitrary branching which can create
>> > duplicate and/or disconnected MAJOR.MINOR.PATCH versions. This type
>> > of branching is expected to be rare, and so BASE will rarely change. When a
>new BASE is created, the MAJOR.MINOR.PATCH reset to starting values.
>>
>> Could you please clarify a bit what BASE means?
>> What would be a different BASE?
>>
>
>The BASE number supports general branching that would cause version number
>conflicts. Branching for firmware releases is not desirable, but it is a practical
>reality. Therefore the versioning scheme must accomodate it. Let's say that a
>high-priority request is made to put specific updates on an old release that said
>customer is locked on. Those updates could include any sort of change including
>interface change. Then we have a sequence like below:
>
>v1.1.0.0   v1.1.0.1   v1.1.0.2   v1.1.0.3   v1.1.1.0
>----O----------O----------O----------O----------O
>                           \
>                            \
>                             \
>                              O----------O
>                          v2.1.1.0   v2.1.1.1
>
>You can see that if we don't have a BASE number that changes from 1 to 2, then
>we end up with duplicated v1.1.0 along the different branches which are not the
>same. As I wrote, this should be a very rare scenario, but it can happen. Maybe
>upstream will always be supplied with releases from the "main" BASE, and you
>can ignore this field, but it needs to be there for other firmware distributions.
>-Jeff
>
>> >
>> > The MAJOR number conforms to the major in semver.org. It increments
>> > on a backwards incompatible change of the interface. It resets to 1
>> > on a change of BASE. The MAJOR number basically works the same
>> > between the current and proposed versioning schemes.
>> >
>> > The MINOR number conforms to the minor in semver.org. It increments
>> > on a backwards compatible change of the interface (new interfaces
>> > that are optional to use). It will also increment on substantial new
>> > internal functionality that doesn't affect the interface but should
>> > be called out to the user. It resets to
>> > 0 on a change of MAJOR. The MINOR number in the current versioning
>> > scheme increments on any backwards compatible change. The proposed
>> > versioning scheme breaks this into the MINOR number just described and the
>PATCH number below.
>> >
>> > The PATCH number conforms to the patch in semver.org. It increments
>> > on a backwards compatible internal change, usually a bug fix. It
>> > resets to 0 on a change of MINOR.
>>
>> I like the idea of MAJOR.MINOR.PATCH following semver.org.
>>
>> I think if we remove the BASE out of picture and just use semver
>> clear, but maybe it is just because I didn't quite understand BASE.
>>
>> >
>> > The MAJOR.MINOR collectively define the interface version. Because
>> > the MINOR may also increment on a substantial internal change, it
>> > doesn't always mark an interface change, e.g. 4.5 and 4.6 may have
>> > identical interfaces. But the determination of interface
>> > compatibility is unchanged, e.g. 4.6 is always backwards compatible with 4.5.
>> >
>> > Each MAJOR.MINOR may continue to receive internal fixes along a
>> > branch even after the main branch for that BASE has moved on to another
>MAJOR.MINOR.
>> > Releases from these fix-only branches increment only the PATCH
>> > number on that MAJOR.MINOR, and therefore remain semantically consistent
>with the main branch.
>> > No change of BASE is therefore needed. Consider an example:
>> >
>> > v1.1.0.0   v1.1.0.1   v1.1.0.2   v1.1.1.0   v1.1.1.1
>> > ----O----------O----------O----------O----------O    <-- main adopts v1.1.1.x
>> >                            \
>> >                             \
>> >                              \
>> >                               O----------O     <-- fixes for interface v1.1.0.x
>> >                           v1.1.0.3   v1.1.0.4
>>
>> This approach is cool and more or less how Mesa handles their
>> releases, except by the fact that their Major is the year and minor is the month.
>>
>> However, on the firmware side I have a concern because we are so far
>> trying to make sure that we have 1-1 relationship on kernel-firmware version.
>>
>> But based on this view and what Anusha told me yesterday it seems that
>> GuC is getting constant releases. With the constant patches we will
>> soon explode linux-firmware.git repository size.
>>
>> But this maybe is something to be solved on linux-firmware side and we
>> make sure that we clean up and remove firmware that were never
>> released in any official Linux kernel. Anusha or Antonio, thoughts?
>>
>> Thanks,
>> Rodrigo.
>>
>
>I expect that i915 will still require a single version of firmware per platform as it
>does today. This change should not impact that other than to require i915 to
>check 4 numbers instead of 2.
>
>It is true that firmware releases are made *internally* (from the firmware team
>to the operating system teams) at a frequent rate. It is up to each OS team to
>decide their own cadence for integrating and distributing those firmware based
>on their unique situation. So the Linux team may filter these releases and update
>the upstream much less frequently.

Rodrigo, it should be a matter of keeping the internal repo clean...maybe more frequently. But We will still be releasing only production signed firmware to upstream linux...which might not be all the versions that gets released to us. I think we should be fine. 

Anusha 
>> >
>> > There is no need to change the BASE because the branching happened
>> > from the last fix (v1.1.0.2) on the main branch prior to the change
>> > of interface (v1.1.1.0). As long as only fixes are applied to
>> > v1.1.0.x, there is no risk of version number clash. All of these
>> > release versions remain semantically connected with one small
>> > caveat. If this set of release versions came sequentially along a
>> > single branch, one could infer that the exact fixes in
>> > v1.1.0.4 were inherited by v1.1.1.0. With this "hidden" branching,
>> > this may not be true as in this example. One would need to review
>> > the v1.1.1.0 release notes to check.
>> >
>> > Please provide any feedback on the proposed change.
>> >
>> > Thanks,
>> > Jeff
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