[PATCH 0/3] drm/exynos: add support for dynamic zpos in DECON and FIMD
Inki Dae
inki.dae at samsung.com
Tue Dec 11 23:48:06 UTC 2018
18. 12. 11. 오후 10:20에 Andrzej Hajda 이(가) 쓴 글:
> Hi again,
>
> It seems I have missed two questions:
>
> On 11.12.2018 09:36, Andrzej Hajda wrote:
>> On 11.12.2018 09:01, Inki Dae wrote:
>>> 18. 12. 11. 오후 4:49에 Andrzej Hajda 이(가) 쓴 글:
>>>> On 11.12.2018 00:45, Inki Dae wrote:
>>>>> Hi Andrzej,
>>>>>
>>>>> 18. 12. 10. 오후 4:35에 Andrzej Hajda 이(가) 쓴 글:
>>>>>> Hi Inki,
>>>>>>
>>>>>> On 10.12.2018 03:25, Inki Dae wrote:
>>>>>>> Hi Andrzej,
>>>>>>>
>>>>>>> 18. 12. 6. 오후 6:38에 Andrzej Hajda 이(가) 쓴 글:
>>>>>>>> Hi Inki,
>>>>>>>>
>>>>>>>> This small patchset adds dynamic zpos support for DECON and FIMD.
>>>>>>> This patch will allow user space to change zpos. However, DECON and FIMD devices have fixed priority of HW overlays.
>>>>>>> This would mean that zpos change by user space doesn't guarantee correct HW overlay priority.
>>>>>>>
>>>>>>> Why do you want to support mutable zpos?
>>>>>> Practically you have patches which proves it works, you can see that
>>>>>> changing zpos value results in adequate change in displayed image.
>>>>>>
>>>>>> Conceptually it is just a matter of disconnecting hardware windows
>>>>>> present in DECON and FIMD from DRM planes which are software entities.
>>>>>>
>>>>>> You can reason about it this way:
>>>>>>
>>>>>> - drm plane is a framebuffer plus informations how it should be
>>>>>> transformed/displayed on DECON/FIMD,
>>>>>>
>>>>>> - hw window in DECON/FIMD is just a channel through which plane is send
>>>>>> to the display.
>>>>>>
>>>>>> DECON and FIMD has fixed hw windows order - windows with lower numbers
>>>>>> are displayed below windows with higher number. To display planes in
>>>>>> given z-order you just need to send them via windows with appropriate
>>>>>> index - farthest plane should go always via win0, closer one via win1,
>>>>>> ..., till the last plane.
>>>>>>
>>>>>> So for example if you have three planes and want to display them in
>>>>>> following order (first one farthest, last one closest):
>>>>>>
>>>>>> plane2, plane1, plane3
>>>>>>
>>>>>> you should map them to planes as follow:
>>>>>>
>>>>>> plane2 -> win0, plane1 -> win1, plane3 -> win2
>>>>>>
>>>>>> then for example plane2 is disabled, we will have following mapping:
>>>>>>
>>>>>> plane1 -> win0, plane3 -> win1, win2 - disabled
>>>>> Plane1 is displayed below Plane3.
>>>> And this is what we wanted, the initial order was: plane2, plane1,
>>>> plane3, first farthest (or lowest if you prefer this naming schema).
>>>>
>>>>
>>>>>> then if you change zorder of planes to: plane3, plane1:
>>>>>>
>>>>>> plane3 -> win0, plane1 -> win1
>>>>> Plane3 is displayed below Plane1 because DECON/FIMD HW aren't able to change HW overlay priroty.
>>>> No, plane3 is displayed below plane1 because we sent it via win0, if we
>>>> want inverse we can send plane3 via win1 and plane1 via win0.
>>>>
>>>>
>>>>> However, user space wanted that Plane1 is displayed below Plane3. Like this, zpos change by user space doesn't guarantee correct HW overlay priority.
>>>> As I said before in this example userspace wanted plane3 below plane1,
>>>> and as I wrote in comment above any order of planes user want driver is
>>>> able to realize with this patch.
>>>>
>>>>
>>>>> And there is no any reason to change zpos in user space excepting Mixer device which supports HW overlay priority change.
>>>> Lack of special registry for manipulating windows order does not mean it
>>>> cannot support dynamic zpos.
>>>>
>>> Why changing zpos in user space is required?
>
>
> I didn't say it is required, but usually it is better if the driver
> supports more features than less.
Supporting more feature is ok but without HW support I don't see what benefit there is excepting making user space confusing.
>
>
> Regards
>
> Andrzej
>
>
>>>
>>>>> In fact, we supported mutable zpos before but changed it to immutable with same reason.
>>>> It was just broken if I remember correctly.
>>>>
>>> No, I worked well and real user used it I remember.
>
>
> I tried to find the code in git history, I have found some pre-atomic
> patches for zpos. It is not clear how it worked and why mutable zpos has
> been removed. Do you remember reasons?
>
We was able to configure zpos before with below patch and real user used it for long time,
commit 00ae67cf26fad3889e71e3bdbec012b1f938dc0e
Author: Joonyoung Shim <jy0922.shim at samsung.com>
Date: Wed Jun 27 14:27:06 2012 +0900
drm/exynos: add property for plane zpos
The exynos drm driver used a specific ioctl - DRM_EXYNOS_PLANE_SET_ZPOS
to set zpos of plane. It can be substitute to property of plane. This
patch adds a property for plane zpos and removes
DRM_EXYNOS_PLANE_SET_ZPOS ioctl.
Signed-off-by: Joonyoung Shim <jy0922.shim at samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park at samsung.com>
Signed-off-by: Inki Dae <inki.dae at samsung.com>
So you said it was just broken wouldn't be true.
Since then, I don't remember whether zpos feature was broken.
But we made decon/fimd's planes to be immutable because they didn't support priority change of HW overlays.
And Marek added mutable zpos support only for Mixer device. As I mentioned already Mixer device is able to change HW overlay priority so it is reasonable,
commit a2cb911eb663b5820dab89f21ce698d68e7cc568
Author: Marek Szyprowski <m.szyprowski at samsung.com>
Date: Wed Dec 16 13:21:44 2015 +0100
drm/exynos: mixer: set window priority based on zpos
'zpos' plane property is configurable, so adjust hardware layers
priority based on the zpos value. 'zpos' value shifted by one can be
used directly as hw priority value and stored to the registers, because
mixer accepts priority values from 1 to 15 (0 means that layer is
disabled).
This patch also changes the default layer priority to match already
exposed initial zpos values. The initial configuration is now:
[top] video > gfx layer1 > gfx layer0 [bottom].
Signed-off-by: Marek Szyprowski <m.szyprowski at samsung.com>
Signed-off-by: Inki Dae <inki.dae at samsung.com>
Thanks,
Inki Dae
>
> Regards
>
> Andrzej
>
>
>
>>>
>>>>> Lastly, your patch made real user broken.
>>>> Who? How?
>>> Window server of Tizen didn't work and you can test it with below image - I didn't check why it doesn't. Anyway, we don't have to break real user.
>>> http://download.tizen.org/snapshots/tizen/unified/latest/images/standard/mobile-wayland-armv7l-tm2/
>>
>> Are you saying it works with latest mainline without my patches?
>>
>>
>> Regards
>>
>> Andrzej
>>
>>
>>> Thanks,
>>> Inki Dae
>>>
>>>> Regards
>>>>
>>>> Andrzej
>>>>
>>>>
>>>>> Thanks,
>>>>> Inki Dae
>>>>>
>>>>>> As you see there is no relation between plane number and window number,
>>>>>> but window number is equal to plane's position in zpos-ordered list of
>>>>>> planes and this is exact value of normalized_zpos field in drm_plane_state.
>>>>>>
>>>>>>
>>>>>> I hope this extended explanation will clarify things.
>>>>>>
>>>>>>
>>>>>> Regards
>>>>>>
>>>>>> Andrzej
>>>>>>
>>>>>>
>>>>>>
>>>>>>> Thanks,
>>>>>>> Inki Dae
>>>>>>>
>>>>>>>> It was tested on tm2 and trats2.
>>>>>>>>
>>>>>>>> Regards
>>>>>>>> Andrzej
>>>>>>>>
>>>>>>>>
>>>>>>>> Andrzej Hajda (3):
>>>>>>>> drm/exynos/decon5433: add dynamic zpos support
>>>>>>>> drm/exynos/fimd: create local helper for disabling hardware window
>>>>>>>> drm/exynos/fimd: add dynamic zpos support
>>>>>>>>
>>>>>>>> drivers/gpu/drm/exynos/exynos5433_drm_decon.c | 23 +++++-----
>>>>>>>> drivers/gpu/drm/exynos/exynos_drm_fimd.c | 42 ++++++++-----------
>>>>>>>> 2 files changed, 29 insertions(+), 36 deletions(-)
>>>>>>>>
>>>>
>>
>>
>
>
>
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