Re: [PATCH v10 00/17] drm/exynos: atomic modesetting support

Inki Dae
2015-06-18T04:36:55Z

On 2015년 06월 17일 23:33, Gustavo Padovan wrote:
> Hi Inki,
>
> 2015-06-17 Inki Dae <inki.dae@samsung.com>:
>
>> Hi Gustavo,
>>
>> On 2015년 06월 17일 05:35, Gustavo Padovan wrote:
>>> HI Inki,
>>>
>>> 2015-06-15 Inki Dae <inki.dae@samsung.com>:
>>>
>>>> Hi Gustavo,
>>>>
>>>> On 2015년 06월 02일 00:04, Gustavo Padovan wrote:
>>>>> From: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
>>>>>
>>>>> Hi,
>>>>>
>>>>> Here goes the full support for atomic modesetting on exynos. I've
>>>>> split the patches in the various phases of atomic support.
>>>>>
>>>>> v2: fixes comments by Joonyoung
>>>>> - remove unused var in patch 09
>>>>> - use ->disable instead of outdated ->dpms in hdmi code
>>>>> - remove WARN_ON from crtc enable/disable
>>>>>
>>>>> v3: fixes comment by Joonyoung
>>>>> - move the removal of drm_helper_disable_unused_functions() to
>>>>> separated patch
>>>>>
>>>>> v4: add patches that remove unnecessary calls to disable_plane()
>>>>>
>>>>> v5: fixes NULL CRTC crash on planes updates (reported by Inki and Tobias)
>>>>>
>>>>> v6: rebase on latest exynos_drm_next
>>>>>
>>>>> v7: fix comments by Joonyoung
>>>>> - fix two checkpatch errors
>>>>> - remove extra crtc->commit() call
>>>>> - check for null fb on exynos_check_plane()
>>>>>
>>>>> v8: fix comments by Joonyoung
>>>>> - fix merge error
>>>>> - move drm_crtc_vblank_get to the commit that introduces atomic pageflip
>>>>> - remove .prepare() in the apropiated patch
>>>>> - add a new patch to move exynos_drm_crtc_disable()
>>>>>
>>>>> v9: * fix comments by Joonyoung
>>>>> - also remove encoder .prepare()
>>>>> - do not shift exynos_update_plane() parameters
>>>>> - remove unused .mode_set() and .mode_set_base()
>>>>> * add specific exynos .atomic_commit()
>>>>> * add split of exynos_crtc->ops->dpms() into enable() and disable()
>>>>> * add other atomic clean ups
>>>>>
>>>>> v10: * fix comments by Joonyoung
>>>>> - add more comments on exynos_atomic_commit()
>>>>> - make exynos_crtc's .enable and .disable void
>>>>
>>>> I found out one issue that refresh rate gets low with display extension
>>>> mode test.
>>>>
>>>> I tested it with two crtc drivers - vidi and fimd on Trats2 board. Here
>>>> is how to test it,
>>>>
>>>> #echo 1 > /sys/devices/platform/exynos-drm-vidi/connection
>>>> # modetest -M exynos -v -s 31@29:720x1280 -s 23@21:640x480
>>>> setting mode 720x1280-60Hz@XR24 on connectors 31, crtc 29
>>>> setting mode 640x480-75Hz@XR24 on connectors 23, crtc 21
>>>> freq: 20.00Hz
>>>> freq: 20.00Hz
>>>>
>>>> As you can see, refresh rate is 20.
>>>>
>>>> Below is the result without atomic patch series,
>>>> # modetest -M exynos -v -s 31@29:720x1280 -s 23@21:640x480
>>>> setting mode 720x1280-60Hz@XR24 on connectors 31, crtc 29
>>>> setting mode 640x480-75Hz@XR24 on connectors 23, crtc 21
>>>> freq: 60.18Hz
>>>> freq: 49.09Hz
>>>>
>>>> I can see 60Hz for FIMD and 49Hz for vidi.
>>>
>>> I gave this a try and figured out that this might be a vidi specific
>>> problem. If I try VIDI and FIMD I get the same results as you but with
>>> Mixer and FIMD(the setup I actually use to test) everything works fine.
>>
>> Hm... Did Mixer and FIMD combination really work correctly with
>> extension mode?
>
> Yes.
>
> collabora@singularity:~$ modetest -M exynos -s 31:1920x1080 -v -s
> 25:1366x768
> setting mode 1920x1080-60Hz@XR24 on connectors 31, crtc 29
> setting mode 1366x768-60Hz@XR24 on connectors 25, crtc 23
> freq: 55.82Hz
> freq: 55.38Hz
> freq: 55.30Hz
> freq: 55.38Hz
> freq: 55.30Hz
> freq: 55.38Hz
> freq: 55.30Hz
> freq: 55.38Hz
> freq: 55.30Hz
> freq: 55.38Hz
>
>>
>>> So somehow my patches caused a regression on vidi that I'm still
>>> ivestigating.
>>
>> I think this issue is because page flip operations are performed in
>> atomic: if I see correctly, when page flip is requested by modetest, the
>> call flow is as follows,
>>
>> drm_atomic_helper_page_flip
>> drm_atomic_async_commit
>> exynos_atomic_commit
>> ...
>> drm_atomic_helper_wait_for_vblanks
>> ...
>>
>> However, the function, drm_atomic_helper_wait_for_vblanks called by
>> exynos_atomic_commit, waits for the vblank completion of each crtc
>> driver . See wait_event_timeout function call in
>> drm_atomic_helper_wait_for_vblanks function.
>>
>> This means that a page flip request of a crtc driver cannot be performed
>> until the vblank completion of another crtc driver. I think you should
>> have implemented exynos_atomic_commit function asynchronously, not
>> synchronously like you did. So it seems that this function should be
>> re-implemented.
>
> I have a patch for it already. I'll resend a v2 of my last series.

Can you post it now?

Thanks,
Inki Dae

>
>>
>> If my analysis is correct and you cannot post the change set within this
>> week, I'm not sure whether the atomic patch series should go to
>> mainline. Anyway, I will decide it and have a pull-request at the end of
>> this week at least.
>
> We have about 3 months to fix this, until v4.2 is out, not one week. And
> it is working for FIMD and Mixer.
>
> Gustavo
>

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