linux-kernel - Re: [RFC PATCH 0/3] staging: remove fbdev drivers

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Message-ID: <20161208142223.et35q56hfxs6sb5f@phenom.ffwll.local>
Date:   Thu, 8 Dec 2016 15:22:23 +0100
From:   Daniel Vetter <daniel@...ll.ch>
To:     Geert Uytterhoeven <geert@...ux-m68k.org>
Cc:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Tomi Valkeinen <tomi.valkeinen@...com>,
        Linux Fbdev development list <linux-fbdev@...r.kernel.org>,
        DRI Development <dri-devel@...ts.freedesktop.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>,
        Noralf Trønnes <noralf@...nnes.org>,
        Sudip Mukherjee <sudipm.mukherjee@...il.com>,
        Teddy Wang <teddy.wang@...iconmotion.com>,
        Arnaud Patard <arnaud.patard@...-net.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [RFC PATCH 0/3] staging: remove fbdev drivers

Dear dri-devel folks,

My sincere apologies for hitting send on that mail. I got real mad and
angry and typed a mail I shouldn't have submitted - pouring oil into
flames for shit and giggles just doesn't help anyone, and it detracts from
moving things forward and improving the code and drivers and everything in
a friendly and constructive fashion. I want to be part of a great
community, this wasnt :(

/me out and off for a walk

Thanks, Daniel

On Thu, Dec 08, 2016 at 03:02:10PM +0100, Daniel Vetter wrote:
> On Thu, Dec 08, 2016 at 01:15:56PM +0100, Geert Uytterhoeven wrote:
> > On Thu, Dec 8, 2016 at 11:10 AM, Daniel Vetter <daniel@...ll.ch> wrote:
> > > On Thu, Dec 08, 2016 at 12:01:19PM +1100, Benjamin Herrenschmidt wrote:
> > >> On Wed, 2016-11-23 at 10:03 +0200, Tomi Valkeinen wrote:
> > >> > Since the fbdev framework is in maintenance mode and all new display drivers
> > >> > should be made with the DRM framework, remove the fbdev drivers from staging.
> > >> >
> > >> > Note: the patches are created with git format-patch -D, so they can't be
> > >> > applied. Only for review.
> > >>
> > >> I missed the discussion where this decision was made, I admit I am
> > >> unimpressed by it.
> > >>
> > >> DRM drivers don't strike me as suitable for small/slow cores with dumb
> > >> framebuffers or simple 2D only accel, such as the one found in the ASpeed
> > >> BMCs.
> > >
> > > We have a helper for simple drivers now, if you take into account the
> > > massive helper libraries for everything that comes along with drm I expect
> > > if even dumb panels behind slow spi buses drm is now the more suitable
> > > subsytem.
> > 
> > This has been going on your years:
> >   1. Fbdev is obsolete, everybody should use DRM instead!
> >   2. Can you please point me to a small sample driver for a dumb frame buffer?
> >   3. Several are being written, but none of them is upstream yet.
> >   4. Goto 1.
> 
> Wut. We have like 20+ small atomic drivers nowdays.
> 
> > >> With drmfb you basically have to shadow everything into memory & copy
> > >> over everything, and locks you out of simple 2D accel. For a simple text
> > >> console the result is orders of magnitude slower and memory hungry than
> > >> a simple fbdev.
> > >
> > > Not true, we have full fbdev emulation, and drivers can implement the 2d
> > > accel in there. And a bunch of them do. It's just that most teams decided
> > > that this is pointless waste of their time.j
> > >
> > >> At least that was the case last I looked at the DRM stuff with Dave,
> > >> maybe things have changed...
> > >>
> > >> Not everything has a powerful 3D GPU.
> > >
> > > That's correct, and drm can cope. And compared to fbdev there's a very
> > > active community who improves&refactors it every kernel release to make it
> > > even better. Since about 2 years (when atomic landed) we merge new drivers at
> > > a rate of 2-3 per kernel release, and those new drivers get ever simpler
> > > and smaller thanks to all this work.
> > 
> > You mean the kind of refactoring that causes severe merge conflicts between
> > drm-next and Linus' tree about every single day?
> > (sorry, couldn't resist ;-)
> 
> Yeah, for a subsystem that only consists of 10% of the overall kernel (by
> patch count) we do an extremly shitty job. Maybe we should just all slow
> down and stop merging support for new hw, and fuck Android and CrOS and
> the billions of devices that don't ship upstream, who cares about those
> folks.
> 
> If you're this good at mainting gpu and display subsystems, maybe you want
> to take over?
> -Daniel
> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch