linux-kernel - Re: [PATCH 0/3] drm/exynos: Kconfig dependency fixes

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Message-id: <56FA03A3.1090205@samsung.com>
Date:	Tue, 29 Mar 2016 13:25:07 +0900
From:	Seung-Woo Kim <sw0312.kim@...sung.com>
To:	Javier Martinez Canillas <javier@....samsung.com>
Cc:	linux-kernel@...r.kernel.org,
	Krzysztof Kozlowski <k.kozlowski@...sung.com>,
	linux-samsung-soc@...r.kernel.org, dri-devel@...ts.freedesktop.org,
	Tobias Jakobi <tjakobi@...h.uni-bielefeld.de>,
	Kyungmin Park <kyungmin.park@...sung.com>,
	Kukjin Kim <kgene@...nel.org>,
	linux-arm-kernel@...ts.infradead.org,
	Seung-Woo Kim <sw0312.kim@...sung.com>,
	m.szyprowski@...sung.com
Subject: Re: [PATCH 0/3] drm/exynos: Kconfig dependency fixes

Hello Javier,

On 2016년 03월 29일 11:41, Javier Martinez Canillas wrote:
> Hello Seung-Woo,
> 
> Thanks a lot for your feedback.
> 
> On 03/28/2016 09:46 PM, Seung-Woo Kim wrote:
>> Hi Javier,
>>
>> On 2016년 03월 29일 10:28, Javier Martinez Canillas wrote:
>>> Hello Inki,
>>>
>>> This patch series contains some fixes for the Kconfig symbol dependencies
>>> of the Exynos DRM driver. They make sure that the Exynos DRM components
>>> and the media platform drivers that makes use of the same HW IP block are
>>> not enabled at the same time.
>>>
>>> Best regards,
>>> Javier
>>>
>>>
>>> Javier Martinez Canillas (3):
>>>   drm/exynos: Use VIDEO_SAMSUNG_S5P_G2D=n as G2D Kconfig dependency
>>>   drm/exynos: Use VIDEO_SAMSUNG_EXYNOS_GSC=n as GSC Kconfig dependency
>>>   drm/exynos: Make DRM_EXYNOS_FIMC depend on VIDEO_S5P_FIMC=n
>>
>> In G2D case, there is only one instance, but for the other cases, there
>> are several instances and in my environment, I enable both drivers on
>> v4l2 and drm FIMC/GSC.
>>
>> So, IMHO, the not-enabled v4l2 dependency is not really required for drm
>> fimc and drm gsc.
>>
> 
> I'm confused, it was you who added the depends on !VIDEO_SAMSUNG_EXYNOS_GSC
> for DRM_EXYNOS_GSC in commit aeefb36832e5 ("drm/exynos: gsc: add device tree
> support and remove usage of static mappings").

Yes, you are right. Originally, my goal on the GSC was bringing optional
flag for setting isp mode or wb mode like FIMC in tizen.org git tree.

https://review.tizen.org/git/?p=platform/kernel/linux-exynos.git;a=blobdiff;f=Documentation/devicetree/bindings/media/exynos5-gsc.txt;h=d526777a3abd04d244c46fdd729e3df93bb86917;hp=0604d42f38d1941526d47ad11a958a2a83797f97;hb=751cd6d88d9620c83042641b52fdd244408a3947;hpb=7c7ab44f86d64ba6a6733da8f201a26a6c0e807f

But only devicetree part of GSC was upstreamed and simultaneous enabling
both v4l2 gsc and drm gsc driver is removed. The only reason I set both
driver simultaneously was enabling video codec, exynos-mfc with gsc to
convert RGB plane.

I know Marek already has plan to integrate yuv plane feature of GSC to
DRM KMS. Also, for GSC, simultaneous setup is alredy remove, so your
patch seems better.

> 
>>>From the commit message "The driver cannot be used simultaneously with V4L2
> Mem2Mem GScaller driver thought". Did that assumption changed and the depend
> should be removed then? or maybe I misunderstood what you meant.
> 
> Now, I'm not really sure about FIMC either, it was feedback I got from this
> patch [0]. Could you please take a look to that and let me know if enabling
> these drivers simultaneously makes sense then?

About FIMC, there is still simultaneous setup for both v4l2 and drm
driver with devicetree binding flags, samsung,isp-wb and samsung,lcd-wb.

If on the FIMC instance of dt node, samsung,lcd-wb is set, then drm
driver is probed, otherwise v4l2 driver is probed.

Simultaneous FIMC driver is also only for RGB converting of video codec
planes like GSC at least to me.

Marek, do you have any idea about the simultaneous setup for fimc and gsc?

Best Regards,
- Seung-Woo Kim

> 
>> Best Regards,
>> - Seung-Woo Kim
>>
>>>
>>>  drivers/gpu/drm/exynos/Kconfig | 6 +++---
>>>  1 file changed, 3 insertions(+), 3 deletions(-)
>>>
>>
> 
> [0]: https://lkml.org/lkml/2016/3/23/292
> 
> Best regards,
> 

-- 
Seung-Woo Kim
Samsung Software R&D Center
--