Hi Laszlo,
On Fri, Nov 09, 2018 at 05:46:47PM +0100, Laszlo Ersek 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.
Well, I don't really have a horse in this race, but since you've
directed the email at me (at least that's what mailman makes it look
like :) I'll state my opinion:
My leaning would be towards reverting the reverts.
My workstation runs Debian Stretch, and the QEMU included there is
2.8.1. So a current "stable" distribution would be affected ...
... for people who run bleeding edge EDK2 on stable-distro-provided
QEMU. Which is why it's only leaning.
There is no such thing as too many reverts.
/
Leif
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