media-libs/libsdl2: add USE to enable hidapi-libusb flag

[Tatsh]

Package-Manager: Portage-3.0.28, Repoman-3.0.3

Yuzu and other emulators need this flag enabled if SDL is to be used as a shared library. Without it, motion controls silently fail.

Yuzu is also in GURU but only builds from Git master and submodules for the time being.

My Yuzu ebuild

[gentoo-bot]

Pull Request assignment

Submitter: @Tatsh
Areas affected: ebuilds
Packages affected: media-libs/libsdl2

media-libs/libsdl2: @gentoo/games

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[gentoo-repo-qa-bot]

Pull request CI report

Report generated at: 2021-10-11 19:05 UTC
Newest commit scanned: a56ddfc
Status: ✅ good

There are existing issues already. Please look into the report to make sure none of them affect the packages in question:
https://qa-reports.gentoo.org/output/gentoo-ci/b385f3d743/output.html

[gentoo-repo-qa-bot]

Pull request CI report

Report generated at: 2021-10-11 19:35 UTC
Newest commit scanned: 0a929f6
Status: ✅ good

There are existing issues already. Please look into the report to make sure none of them affect the packages in question:
https://qa-reports.gentoo.org/output/gentoo-ci/36f3f83b92/output.html

[chewi]

Thanks for this, but could we call the flag raw-hid or something to reflect what it actually does?

[Tatsh]

Yes. Happy to change it.

There are two variants of HIDAPI usage: HIDAPI+libusb and HIDAPI without libusb. Do we want a USE flag for either of these? Currently without anything only HIDAPI without libusb support is built (based on auto detection).

I propose having +hidapi (+ because most people would want it and it is the default; precedent: app-misc/g810-led) and then specify USE="hidapi libusb" to this variant.

EDIT: libusb is preceded by several packages which is why I went with it.

[Tatsh]

This change would require setting matching KEYWORDS in dev-libs/hidapi ebuild, which would include stabilising SPARC and others. Not sure if that would be desired.

[ionenwks]

This change would require setting matching KEYWORDS in dev-libs/hidapi ebuild, which would include stabilising SPARC and others. Not sure if that would be desired.

Can also mask the USE on these arches -- which can be temporary until it's keyworded, or permanent if it's broken or there's no interest. Not that had a close look at what it's good for, just saying.

[Tatsh]

This change would require setting matching KEYWORDS in dev-libs/hidapi ebuild, which would include stabilising SPARC and others. Not sure if that would be desired.

Can also mask the USE on these arches -- which can be temporary until it's keyworded, or permanent if it's broken or there's no interest. Not that had a close look at what it's good for, just saying.

Done I think (as far as I can tell editing in profiles/ is how that is done). I hope the descriptions are good enough.

[gentoo-repo-qa-bot]

Pull request CI report

Report generated at: 2021-10-13 10:30 UTC
Newest commit scanned: ab0ab08
Status: ✅ good

There are existing issues already. Please look into the report to make sure none of them affect the packages in question:
https://qa-reports.gentoo.org/output/gentoo-ci/5a36bd0aee/output.html

[Tatsh]

bump?

[chewi]

For future reference, you can use package.use.stable.mask to mask flags on stable only. This is hopefully just temporary anyway. I'd request some keywording/stabilisation now but it looks like hidapi might be bumped soon.

[chewi]

Sorry, I realised afterwards that I'd overlooked some things here and had to revert it.

1. This doesn't actually use the external hidapi package, but a bundled copy within SDL2.
2. The libusb library is loaded dynamically though dlopen but is possibly unused.
3. The changes were made to the stable ebuild instead of a new revision.

I'm not sure whether the first point can be easily addressed properly. It doesn't look like any consideration was made upstream for using an external copy of the library. A patch with an upstream submission would be much appreciated.

On the second point, most external libraries have a --disable-*-shared option but libusb does not. Setting require_hidapi_libusb=yes hacks around it, but the library seemingly gets dropped by -Wl,--as-needed anyway, as though it weren't being used at all. I'm not sure, but the impression I get is that libusb is only used on BSD. We don't really claim to support BSD like we used to, so this could be dropped, but I would accept changes for this if it were handled properly.

If it hadn't been for all the above, I might have let the change to a stable ebuild slide.

[chewi]

Looking closer at libusb, I'm even more confused. SDL_hidapi.c suggests it only supports being loaded dynamically, but configure forces it to be explicitly linked on BSD. I think it's only outright required on BSD regardless. It's unclear whether there's any benefit in enabling it on other platforms.

[chewi]

Okay, I see that it allows you to use Nyko and EVORETRO GameCube adaptors, but I think that's all.

[Tatsh]

Thanks for responding.

The point of this change is to make motion (accelerometer, etc) work with the Nintendo Switch Pro Controller mainly.

Within Yuzu, without this flag, SDL will incorrectly see the Pro Controller as two devices rather than one, and motion will not work correctly. I am not sure what the magic is underneath.

I guess I will have to dig into making it work with external libusb.

[tiagodfer]

Hey guys, what's the current state of this request? Is there anyway to have motion detected by SDL2?

[Tatsh]

It's a pain to make this proper for Gentoo so it's on hold.