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

From: Daniel Vetter <daniel@ffwll.ch>
To: "Geert Uytterhoeven" <geert@linux-m68k.org>,
	"Thomas Petazzoni" <thomas.petazzoni@free-electrons.com>,
	"Benjamin Herrenschmidt" <benh@kernel.crashing.org>,
	"Tomi Valkeinen" <tomi.valkeinen@ti.com>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"Noralf Trønnes" <noralf@tronnes.org>,
	"Sudip Mukherjee" <sudipm.mukherjee@gmail.com>,
	"Teddy Wang" <teddy.wang@siliconmotion.com>,
	"Arnaud Patard" <arnaud.patard@rtp-net.org>,
	"DRI Development" <dri-devel@lists.freedesktop.org>,
	"Linux Fbdev development list" <linux-fbdev@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH 0/3] staging: remove fbdev drivers
Date: Fri, 9 Dec 2016 09:30:44 +0100	[thread overview]
Message-ID: <20161209083044.vr23mrvxovcpkutj@phenom.ffwll.local> (raw)
In-Reply-To: <20161208152134.wnv4j4i6m5xpoycp@phenom.ffwll.local>

On Thu, Dec 08, 2016 at 04:21:34PM +0100, Daniel Vetter wrote:
> [back from my walk, the sunset here is stellar ;-)]
> 
> On Thu, Dec 08, 2016 at 03:44:30PM +0100, Geert Uytterhoeven wrote:
> > Hi Thomas,
> > 
> > On Thu, Dec 8, 2016 at 3:37 PM, Thomas Petazzoni
> > <thomas.petazzoni@free-electrons.com> wrote:
> > > On Thu, 8 Dec 2016 15:22:09 +0100, Geert Uytterhoeven wrote:
> > >> > Wut. We have like 20+ small atomic drivers nowdays.
> > >>
> > >> That's fast! Only two weeks ago you said:
> > >>
> > >> | Bummer, they still haven't landed. But afaik there's at least 4 of
> > >> | them floating around in various places ...
> > >
> > > You're not talking about the same thing I believe.
> > >
> > > When Daniel says "small atomic drivers", he talks about the relatively
> > > small DRM drivers for SoC display controllers, such as the ones you can
> > > find in ARM SoCs.
> > >
> > > When you say "small driver", you're thinking about drivers for I2C or
> > > SPI connected displays.
> > 
> > No, I wasn't thinking about I2C or SPI connected displays, but about simple
> > dumb memory-mapped frame buffers, which is what fbdev was initially
> > developed for.
> 
> Yeah, small drivers like these we have piles now, things exploded a lot
> after atomic landed two years ago. And they seem to shrink with every
> release a bit more (since lots more drivers gives you lots more insight
> into what other refactorings would make sense). Those we have a big pile
> of, and nowadays (at least with developers expirienced with upstream, but
> not necessarily with drm) it takes but a few weeks from initial submission
> to getting them merged.
> 
> What we don't yet have a nice tidy example driver of is the even simpler
> "dumb framebuffer behind a slow bus with explicit/manual upload", for like
> small i2c/spi panels (and conceptually also usb, even though there bw and
> panel size are a bit scaled up). We've gained some really nice helpers for
> this this year, and there's 3 drivers in-flight to make use of it. But
> since that's right now just a hobbyist effort it's moving a bit slower
> (and I was mistaken a few weeks back where I assumed that one of them
> landed already).

Correction, MXSFB just landed, which is the first driver using the simple
display pipe helpers.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch