Re: [PATCH v14 0/3] Add drm driver for Rockchip Socs

[Rob Clark <robdclark@gmail.com>]

On Thu, Nov 27, 2014 at 4:56 PM, Arnd Bergmann <arnd@arndb.de> wrote:
> On Thursday 27 November 2014 14:05:00 Daniel Kurtz wrote:
>> On Thu, Nov 27, 2014 at 2:08 AM, Mark yao <mark.yao@rock-chips.com> wrote:
>> >
>> > On 2014年11月27日 10:12, Dave Airlie wrote:
>> >>>>
>> >>>>
>> >>> Hi Dave
>> >>>      Do you mean that I need send you a branch, based on drm-next, merge with
>> >>> iommu tree and rockchip drm?
>> >>
>> >> Yes, grab drm-next, git pull the arm/rockchip branch from Joerg's
>> >> tree, put rockchip drm
>> >> patches on top, send me pull request.
>> >>
>> >> I'll validate it then.
>> >>
>> >> Dave.
>> >>
>> > Hi Dave
>> >     I have send a pull request to you, with Joerg's iommu arm/rockchip branch.
>> >
>> >     I got a same problem when use "make multi_v7_defconfig" as Heiko said:
>> >         drivers/video/fbdev/Kconfig:5:error: recursive dependency detected!
>> >         drivers/video/fbdev/Kconfig:5:    symbol FB is selected by DRM_KMS_FB_HELPER
>> >         drivers/gpu/drm/Kconfig:34:    symbol DRM_KMS_FB_HELPER is selected by DRM_ROCKCHIP
>> >         drivers/gpu/drm/rockchip/Kconfig:1:    symbol DRM_ROCKCHIP depends on ARM_DMA_USE_IOMMU
>> >         arch/arm/Kconfig:95:    symbol ARM_DMA_USE_IOMMU is selected by VIDEO_OMAP3
>> >         drivers/media/platform/Kconfig:96:    symbol VIDEO_OMAP3 depends on VIDEO_V4L2
>> >         drivers/media/v4l2-core/Kconfig:6:    symbol VIDEO_V4L2 depends on I2C
>> >         drivers/i2c/Kconfig:7:    symbol I2C is selected by FB_DDC
>> >         drivers/video/fbdev/Kconfig:59:    symbol FB_DDC is selected by FB_CYBER2000_DDC
>> >         drivers/video/fbdev/Kconfig:374:    symbol FB_CYBER2000_DDC depends on FB_CYBER2000
>> >         drivers/video/fbdev/Kconfig:362:    symbol FB_CYBER2000 depends on FB
>> >
>> >     I was confused how to solve the recursive dependency, remove depends on ARM_DMA_USE_IOMMU & IOMMU_API?
>>
>> The "depends on ARM_DMA_USE_IOMMU & IOMMU_API" was suggested by Arnd
>> Bergmann during code review (originally they were selected).
>>
>> Removing them definitely fixes the dependency recursion.
>> Also, since they are both already selected by ROCKCHIP_IOMMU,
>> everything will build correctly.
>> So, this sounds good to me, but I am no expert on Kconfig.
>>
>
> I think the problem here is VIDEO_OMAP3 (among others), it should do the
> same as rockchips and use 'depends on' instead of 'select'.
>
> Another problem is the 'select I2C' in FB_DDC, but that would be much harder
> to fix.

that 'select I2C' is the source of many loops..  I'd looked at it
briefly before, but then ran away in despair.

BR,
-R

>         Arnd