Re: [gentoo-dev] Suggestions for simplifying VIDEO_CARDS situation

[Roy Bamford <neddyseagoon@gentoo.org>]

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On 2018.06.17 08:49, Brian Dolbec wrote:
> On Sat, 16 Jun 2018 21:40:10 -0700
> Matt Turner <mattst88@gentoo.org> wrote:
> 
> > Hello,
> > 
> > VIDEO_CARDS is an annoying mess. We used to have radeon, intel, and
> > some others in media-libs/mesa's VIDEO_CARDS. radeon and intel
> > corresponded to disparate sets of drivers -- VIDEO_CARDS=radeon has
> > meant classic r100, r200, r300, and r600 drivers and gallium r600
> and
> > radeonsi drivers. VIDEO_CARDS=intel has meant classic i915 and i965
> > drivers as well as gallium i915.
> > 
> > I added more-specific VIDEO_CARDS for those separate drivers a few
> > years ago, so that users could set VIDEO_CARDS="radeon radeonsi" and
> > only get the one radeonsi driver they actually wanted while still
> > enabling support for x11-libs/libdrm's radeon support code which is
> > used by most of those radeon drivers. Of course some users want this
> > control and others don't care at all.
> > 
> > The confusion comes in with "classic" DRI drivers vs Gallium
> drivers.
> > The Gallium abstraction layer allows a hardware driver to handle
> > multiple APIs -- OpenGL, D3D9, OpenCL, video decode APIs, etc. For
> > instance, users try to build the classic i965 driver (there is no
> > Gallium driver for this hardware) with USE=opencl or USE=vaapi and
> > don't understand why they didn't get what they wanted (or
> REQUIRED_USE
> > prevents them from doing so).
> > 
> > Should of Mesa's USE flags, d3d9, llvm, lm_sensors, opencl, openmax,
> > unwind, vaapi, vdpau, xa, and xvmc are Gallium-only. Should I make a
> > USE_EXPAND for Gallium-only options to attempt to avoid confusion?
> > Another point of confusion: not all Gallium drivers support all of
> > these features. For instance only the r600 and radeonsi drivers
> > support OpenCL. How to best handle this?
> > 
> > It seems like at one extreme you build an extensive set of
> > REQUIRED_USE conditions that force users to micromanage their USE
> > flags, or you let them enable all sorts of impossible combinations
> and
> > deal with the confused bug reports.
> > 
> > I would like to somehow get rid of the 'classic' and 'gallium' USE
> > flags entirely, but I'm not totally sure how. Maybe I can enable
> them
> > dependent on VIDEO_CARDS...
> > 
> > Suggestions welcome.
> > 
> 
> What about creating a tiny pkg that has all the combinations in a
> dictionary and can set the USE and VIDEO_CARDS flags according to the
> video card(s) you have.
> 
> This would be along the same lines as the
> app-portage/cpuid2cpuflags pkg.  Then the pkg is updated as new
> drivers
> and combinations are changed.  Perhaps have it run in pkg_postisnt to
> print any irregularities it finds and ewarn they need fixing.
> 
> -- 
> Brian Dolbec <dolsen>
> 
> 
> 
> 

That would break for cross compiling.  My Raspberry PI has a VC4
GPU but I build things on an AMD64 box.

Any autodetection needs an emergency manual override, even if its
hidden behind the I_KNOW_WHAT_I_AM_DOING flag.

-- 
Regards,

Roy Bamford
(Neddyseagoon) a member of
elections
gentoo-ops
forum-mods

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