Re: [urgent] Soft Feature Freeze has started since Nov.1 for dk2-stable201811

[Phil Dennis-Jordan <lists@philjordan.eu>]

Hi Laszlo,

On Fri, Nov 9, 2018 at 5:47 PM Laszlo Ersek <lersek@redhat.com> wrote:
>
> + Yuchenlin, + Gerd, + both Phils
>
> On 11/07/18 20:13, Laszlo Ersek wrote:
>
> >>> For example, I reviewed and pushed 4 patches yesterday (on 2018-Nov-06):
> >>>
> >>>   1  e038bde2679b Revert "OvmfPkg/QemuVideoDxe: list "UnalignedIoInternal.h" in the INF file"
> >>>   2  98856a724c2a Revert "OvmfPkg/QemuVideoDxe: VMWare SVGA device support"
> >>>   3  438ada5aa5a1 Revert "OvmfPkg/QemuVideoDxe: Helper functions for unaligned port I/O."
> >>>   4  328409ce8de7 Revert "OvmfPkg: VMWare SVGA display device register definitions"
> >>>
> >>> which are the first four patches (out of five) from the following
> >>> series:
> >>>
> >>>   [edk2] [PATCH v2 0/5] OvmfPkg: simply use the Bochs interface for vmsvga
> >>>
> >>> These reverts are arguably not bugfixes; they are preparation for
> >>> re-implementing a feature from scratch (the last patch in that series).
> >>> Thus, had I known we were already in the Soft Feature Freeze, I wouldn't
> >>> have pushed them, because the review was not complete before the soft
> >>> freeze start.
> >>>
> >>> But I had just returned from a week (or more) of PTO, there was no
> >>> announcement on the list yet, and I didn't remember the wiki page.
> >>>
> >>> (In the technical sense, the reverts are not disruptive, luckily; they
> >>> remove code that is dead anyway.)
>
> I've given this more thought.
>
> The reverts indeed remove dead code, but the code in question is dead
> *only* on QEMU v2.10+. On QEMU v2.9 and earlier, the code is not dead.
>
> (See the original discussion in the thread "[edk2] [PATCH] OvmfPkg:
> initialize bochs when initializing vmsvga".)
>
> This means that, with only the first four patches applied from the
> series (= the reverts), and with the fifth patch (= the clean
> re-implementation of the feature) postponed, people running
> edk2-stable201811 on *old* -- v2.9 or older -- QEMU, with VMW SVGA, will
> suffer a regression.
>
> So that leaves me with a question. Should I revert the first four
> patches now, for edk2-stable201811? (I.e., revert the reverts -->
> re-instate the incorrect VMW SVGA driver impl, that happens to work on
> v2.9 and earlier.)
>
> ... Note that upstream QEMU no longer supports (= maintains stable
> branches) for v2.9 and earlier releases. The QEMU homepage
> <https://www.qemu.org/> currently advertizes:
> - 3.1.0-rc0
> - 3.0.0
> - 2.12.1
> - 2.11.2
>
> Personally I'm leaning towards keeping the reverts for
> edk2-stable201811. (v2.9 is really old, and the VMW SVGA device model is
> virtually unused.) For my professional integrity though, I must ask this
> question publicly.

I suspect the number of users relying on this feature is small, and I
have my doubts that this group are running an unpatched snapshot of
the master branch, let alone a stable OVMF release. But I don't have
data for this, only anecdotal evidence. I personally won't be losing
much sleep over it assuming we fix it for ~all versions of Qemu soon
after.

Phil