Re: Re: [PATCH] drm/mediatek: Add MTK Framebuffer-Device (mt7623)

From: Daniel Vetter <daniel@ffwll.ch>
To: Frank Wunderlich <frank-w@public-files.de>
Cc: Daniel Vetter <daniel@ffwll.ch>, CK Hu <ck.hu@mediatek.com>,
	Philipp Zabel <p.zabel@pengutronix.de>,
	David Airlie <airlied@linux.ie>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	dri-devel <dri-devel@lists.freedesktop.org>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	"moderated list:ARM/Mediatek SoC support" 
	<linux-mediatek@lists.infradead.org>,
	Alexander Ryabchenko <d3adme4t@gmail.com>
Subject: Re: Re: [PATCH] drm/mediatek: Add MTK Framebuffer-Device (mt7623)
Date: Thu, 10 Jan 2019 21:02:25 +0100	[thread overview]
Message-ID: <20190110200225.GN21184@phenom.ffwll.local> (raw)
In-Reply-To: <trinity-0da588a3-1277-4421-ad6b-1f6aeb129dd6-1547146897687@3c-app-gmx-bs35>

On Thu, Jan 10, 2019 at 08:01:37PM +0100, Frank Wunderlich wrote:
> Hi Daniel,
> 
> > > Would be good to use the new generic fbdev emulation code here, for even
> > > less code. Or at least know why this isn't possible to use for mtk (and
> > > maybe address that in the core code). Hand-rolling fbdev code shouldn't be
> > > needed anymore.
> > 
> > Back on the mailing list, no private replies please:
> 
> i don't wanted to spam all people with dumb questions ;)

There's no dumb questions, only insufficient documentation :-)

> > For examples please grep for drm_fbdev_generic_setup(). There's also a
> > still in-flight series from Gerd Hoffmann to convert over bochs. That,
> > plus all the kerneldoc linked from there should get you started.
> > -Daniel
> 
> this is one of google best founds if i search for drm_fbdev_generic_setup:
> 
> https://lkml.org/lkml/2018/12/19/305
> 
> not very helpful...
> 
> so i tried kernel-doc
> 
> https://www.kernel.org/doc/html/latest/gpu/drm-kms-helpers.html?highlight=drm_fbdev_generic_setup#c.drm_fbdev_generic_setup
> 
> which is nice function-reference but i've found no generic workflow
> 
> as the posted driver is "only" a driver ported from kernel 4.4 by Alexander, i don't know if this new framework can be used and which parts need to be changed. I only try to bring his code Mainline....
> Maybe CK Hu can help here because driver is originally from him and he knows internals. Or maybe you can help here?
> 
> i personally make my first steps as spare-time kernel-developer :)

There's a ton of in-kernel users of that function already, I meant you can
use those to serve as examples ... If those + the kerneldoc aren't
good enough, then we need to improve them.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch