Re: [RFC] Deprecation and removal of the drm2 driver

On Friday, May 18, 2018, Konstantin Belousov <[email protected]> wrote:

> On Fri, May 18, 2018 at 09:33:40PM +0100, Johannes Lundberg wrote:
> > On Fri, May 18, 2018 at 9:22 PM, Ben Widawsky <[email protected]> wrote:
> >
> > > On 18-05-18 14:15:03, Warner Losh wrote:
> > > > On Fri, May 18, 2018 at 2:12 PM, Johannes Lundberg <
> [email protected]>
> > > > wrote:
> > > >
> > > > >
> > > > >
> > > > > On Fri, May 18, 2018 at 9:03 PM, Warner Losh <[email protected]>
> wrote:
> > > > >
> > > > >> On Fri, May 18, 2018 at 1:30 PM, Steve Kargl <
> > > > >> [email protected]> wrote:
> > > > >>
> > > > >> > On Fri, May 18, 2018 at 09:14:24PM +0200, Andreas Nilsson wrote:
> > > > >> > > On Fri, May 18, 2018, 20:00 Niclas Zeising <
> [email protected]>
> > > > >> wrote:
> > > > >> > >
> > > > >> > > > I propose that we remove the old drm2 driver (sys/dev/drm2)
> from
> > > > >> > > > FreeBSD.  I suggest the driver is marked as deprecated in
> 11.x
> > > and
> > > > >> > > > removed from 12.0, as was done for other drivers recently.
> Some
> > > > >> > > > background and rationale:
> > > > >> > > >
> > > > >> > > > The drm2 driver was the original port of a KMS driver to
> > > FreeBSD.
> > > > >> It
> > > > >> > > > was done by Konstantin Belousov to support Intel graphics
> > > cards, and
> > > > >> > > > later extended by Jean-S??bastien P??dron as well as
> Konstantin to
> > > > >> match
> > > > >> > > > what's in Linux 3.8.  This included unstable support from
> > > Haswell,
> > > > >> but
> > > > >> > > > nothing newer than that.
> > > > >> > > >
> > > > >> > > > For quite some time now we have had the
> > > graphics/drm-stable-kmod and
> > > > >> > > > graphics/drm-next-kmods which provides support for modern
> AMD
> > > and
> > > > >> Intel
> > > > >> > > > graphics cards.  These ports, together with the linuxkpi, or
> > > lkpi,
> > > > >> has
> > > > >> > > > made it significantly easier to port and update our graphics
> > > > >> drivers.
> > > > >> > > > Further, these new drivers cover the same drivers as the old
> > > drm2
> > > > >> > driver.
> > > > >> > > >
> > > > >> > > > What does the community think?  Is there anyone still using
> the
> > > drm2
> > > > >> > > > driver on 12-CURRENT?  If so, what is preventing you from
> > > switching
> > > > >> to
> > > > >> > > > the port?
> > > > >> > > >
> > > > >> > > > Thank you
> > > > >> > > > Regards
> > > > >> > > > --
> > > > >> > > > Niclas Zeising
> > > > >> > > > FreeBSD x11/graphics team
> > > > >> > > > _______________________________________________
> > > > >> > > > [email protected] mailing list
> > > > >> > > > https://lists.freebsd.org/mailman/listinfo/freebsd-current
> > > > >> > > > To unsubscribe, send any mail to
> "freebsd-current-unsubscribe@
> > > > >> > freebsd.org"
> > > > >> > > >
> > > > >> > >
> > > > >> > > Sounds good ( deprecate resp remove ). It causes more
> confusion
> > > and
> > > > >> > > problems and it solves nothing.
> > > > >> > >
> > > > >> >
> > > > >> > Check the Makefiles
> > > > >> >
> > > > >> > % more /usr/ports/graphics/drm-next-kmod/Makefile
> > > > >> >
> > > > >> > ONLY_FOR_ARCHS= amd64
> > > > >> > ONLY_FOR_ARCHS_REASON=  the new KMS components are only
> supported on
> > > > >> amd64
> > > > >> >
> > > > >> > Not to ia32 friendly.
> > > > >> >
> > > > >>
> > > > >> So do people use i386 for desktop? And need the latest KMS stuff?
> > > > >>
> > > > >
> > > > > Yeah I was wondering the same.. If you're running i386, do you
> need drm
> > > > > drivers? Will scfb work an i386? (probably has legacy bios and if I
> > > > > remember correctly, scfb is UEFI only)
> > > > > I do feel sorry for anyone who would have to revert back to VESA...
> > > > >
> > > > > Would it be too much trouble to move it to a port?
> > > > >
> > > >
> > > > If there's someone who needs it for i386, and wants to do the work
> and
> > > > maintain it, we should allow it. But the drm2 maintainers have said
> its
> > > > likely totally broken anyway.
> > > >
> > > > Warner
> > >
> > > As a long time developer in drm/i915, and newly interested in FreeBSD
> (ie.
> > > no
> > > history on the matter), is there some upside and/or desire to have
> native
> > > support, or is the drm-next-kmod solution good enough?
> > >
> >
> > Given the fast evolution of graphics hardware and the amount of code in
> > only the AMD and Intel drivers, keep several native implementations seems
> > impossible, if not wasteful.
> > If you are referring to drm2 in the kernel, that's not much more native
> > than the drm kmods, it still uses a linux compatibility layer (but not as
> > sophisticated).
> Drm2 does not use linux compat layer.
>
> drm2 is probably better on older chipsets which use AGP emulation, i.e.
> everything up to SandyBridge-1. Does drm-next run on gen3 and gen4 at
> all ? In particular, I did obtained real bug reports from people running
> gen 3 hardware. E.g. you cannot run amd64 kernel on T60, but you can run
> i386 and get hw support with drm2.
>
> I still have GM45 (gen4) laptop and use it daily with the drm from the
> tree. I effectively dropped supporting it when half of the HSW support
> code were imported.


I use the in tree DRM2 code on multiple Haswell based laptops. It working
fine. So I prefer to keep it in the tree.

I like to use bigger console, even if I not install anything from ports.


>
> >
> > If we were to focus our effort somewhere, it should be to create a Common
> > Kernel Programming Interface for Linux and *BSDs, especially for DRM
> > drivers. Something a bit more stable that what we see in Linux today.
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