Re: [PATCH] drm: sti: fix sub-components bind

From: Benjamin Gaignard <benjamin.gaignard@linaro.org>
To: Thierry Reding <thierry.reding@gmail.com>
Cc: Russell King <linux@arm.linux.org.uk>,
	"dri-devel@lists.freedesktop.org"
	<dri-devel@lists.freedesktop.org>,
	XinWei Kong <kong.kongxinwei@hisilicon.com>,
	"Liguozhu (Kenneth)" <liguozhu@hisilicon.com>,
	Maxime Coquelin <maxime.coquelin@st.com>
Subject: Re: [PATCH] drm: sti: fix sub-components bind
Date: Thu, 16 Jul 2015 15:08:54 +0200	[thread overview]
Message-ID: <CA+M3ks7Umt_gn=UuKHGen3E5dmY6T0=goyRL_YNGMDS8aOuhvA@mail.gmail.com> (raw)
In-Reply-To: <20150716105912.GA4200@ulmo>

Maxime, as STi DT maintainer, could you give us your point of view ?

If needed I could split the patch in two: one for driver and one for DT.

2015-07-16 12:59 GMT+02:00 Thierry Reding <thierry.reding@gmail.com>:
> On Wed, Jul 15, 2015 at 03:56:41PM +0200, Benjamin Gaignard wrote:
>> It doesn't change any bindings fields, only remove one level of childs on DT.
>> Old DTBs may not work but it will impact only very few peoples and no
>> products so it isn't a problem.
>
> I know, that can be said of most platforms, but the decision was made to
> consider DT a stable ABI, so you can't just go and break it. You'll have
> to take this up with the ARM SoC maintainers. In the past they've been
> known to request people to go through extra pain to avoid breaking DT
> backwards-compatibility.
>
>> The patch fix driver and DT files so I don't think it could create issues.
>
> That doesn't count. Somebody could still be using an old DTB and not be
> able (or unwilling) to reflash it.
>
> Irrespective, you're probably going to want to split up your patch into
> driver and DTS changes. The DTS and binding changes will need to be
> reviewed by the device tree maintainers, and I'd expect that the STi
> maintainers will want to weigh in as well.
>
> Thierry
>
>> 2015-07-15 15:34 GMT+02:00 Thierry Reding <thierry.reding@gmail.com>:
>> > On Wed, Jul 15, 2015 at 03:21:46PM +0200, Benjamin Gaignard wrote:
>> >> Fix misunderstanding in how use component framework.
>> >> drm_platform_init() is now call only when all the
>> >> sub-components are register themselves instead of the
>> >> previous two stages mechanism.
>> >>
>> >> Update devicetree and bindings documentation according
>> >> to this new behavior.
>> >>
>> >> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
>> >> ---
>> >>  .../devicetree/bindings/gpu/st,stih4xx.txt         |  7 +-
>> >>  arch/arm/boot/dts/stih407.dtsi                     | 82 +++++++++++-----------
>> >>  arch/arm/boot/dts/stih410.dtsi                     | 82 +++++++++++-----------
>> >>  drivers/gpu/drm/sti/sti_drm_drv.c                  | 45 ++----------
>> >>  drivers/gpu/drm/sti/sti_hdmi.c                     | 25 ++++---
>> >>  drivers/gpu/drm/sti/sti_tvout.c                    | 46 ++----------
>> >>  6 files changed, 105 insertions(+), 182 deletions(-)
>> >
>> > Isn't this going to break DT ABI? How are you going to ensure backwards-
>> > compatibility with old DTBs?
>> >
>> > Thierry
>>
>>
>>
>> --
>> Benjamin Gaignard
>>
>> Graphic Working Group
>>
>> Linaro.org │ Open source software for ARM SoCs
>>
>> Follow Linaro: Facebook | Twitter | Blog

-- 
Benjamin Gaignard

Graphic Working Group

Linaro.org │ Open source software for ARM SoCs

Follow Linaro: Facebook | Twitter | Blog
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