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.mc...@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 _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
