[PATCH 03/29] drm/amd/display: Complete TODO item: use new DRM iterator

[Andrey Grodzovsky]

On 10/30/2017 01:14 PM, Leo wrote:
>
>
> On 2017-10-30 12:36 PM, Leo wrote:
>>
>>
>> On 2017-10-26 11:06 PM, Andrey Grodzovsky wrote:
>>>
>>>
>>> On 2017-10-26 02:34 PM, Harry Wentland wrote:
>>>> From: "Leo (Sunpeng) Li" <sunpeng.li at amd.com>
>>>>
>>>> Abandon new_crtcs array and use for_each_new iterator to acquire new
>>>> crtcs.
>>>>
>>>> Signed-off-by: Leo (Sunpeng) Li <sunpeng.li at amd.com>
>>>> Reviewed-by: Harry Wentland <Harry.Wentland at amd.com>
>>>> ---
>>>>   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 36 
>>>> +++++++++--------------
>>>>   1 file changed, 14 insertions(+), 22 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c 
>>>> b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>>>> index 442b399a9400..590f80d29b56 100644
>>>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>>>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>>>> @@ -4013,10 +4013,8 @@ static void 
>>>> amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state)
>>>>       struct amdgpu_display_manager *dm = &adev->dm;
>>>>       struct dm_atomic_state *dm_state;
>>>>       uint32_t i, j;
>>>> -    uint32_t new_crtcs_count = 0;
>>>>       struct drm_crtc *crtc;
>>>>       struct drm_crtc_state *old_crtc_state, *new_crtc_state;
>>>> -    struct amdgpu_crtc *new_crtcs[MAX_STREAMS];
>>>>       unsigned long flags;
>>>>       bool wait_for_vblank = true;
>>>>       struct drm_connector *connector;
>>>> @@ -4075,25 +4073,9 @@ static void 
>>>> amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state)
>>>>                   continue;
>>>>               }
>>>> -
>>>>               if (dm_old_crtc_state->stream)
>>>>                   remove_stream(adev, acrtc, 
>>>> dm_old_crtc_state->stream);
>>>> -
>>>> -            /*
>>>> -             * this loop saves set mode crtcs
>>>> -             * we needed to enable vblanks once all
>>>> -             * resources acquired in dc after dc_commit_streams
>>>> -             */
>>>> -
>>>> -            /*TODO move all this into dm_crtc_state, get rid of
>>>> -             * new_crtcs array and use old and new atomic states
>>>> -             * instead
>>>> -             */
>>>> -            new_crtcs[new_crtcs_count] = acrtc;
>>>> -            new_crtcs_count++;
>>>> -
>>>> -            new_crtc_state = drm_atomic_get_new_crtc_state(state, 
>>>> crtc);
>>>>               acrtc->enabled = true;
>>>>               acrtc->hw_mode = new_crtc_state->mode;
>>>>               crtc->hwmode = new_crtc_state->mode;
>>>> @@ -4221,18 +4203,28 @@ static void 
>>>> amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state)
>>>>               dm_error("%s: Failed to update stream scaling!\n", 
>>>> __func__);
>>>>       }
>>>> -    for (i = 0; i < new_crtcs_count; i++) {
>>>> +    for_each_oldnew_crtc_in_state(state, crtc, old_crtc_state,
>>>> +            new_crtc_state, i) {
>>>>           /*
>>>>            * loop to enable interrupts on newly arrived crtc
>>>>            */
>>>> -        struct amdgpu_crtc *acrtc = new_crtcs[i];
>>>> +        struct amdgpu_crtc *acrtc = to_amdgpu_crtc(crtc);
>>>> +        bool modeset_needed;
>>>> -        new_crtc_state = drm_atomic_get_new_crtc_state(state, 
>>>> &acrtc->base);
>>>>           dm_new_crtc_state = to_dm_crtc_state(new_crtc_state);
>>>> +        dm_old_crtc_state = to_dm_crtc_state(old_crtc_state);
>>>> +        modeset_needed = modeset_required(
>>>> +                new_crtc_state,
>>>> +                dm_new_crtc_state->stream,
>>>> +                dm_old_crtc_state->stream);
>>>> +
>>>> +        if (dm_new_crtc_state->stream == NULL || !modeset_needed)
>>>> +            continue;
>>>
>>> I feel it's a bit future bug prone to repeat the 2 checks above from 
>>> the initial
>>> for_each_crtc_in_state loop, somebody makes changes there and forget 
>>> about this loop.
>>> The array is ugly but it avoids logic duplication.
>>
>> I think a better fix would be to combine this for_each section with the
>> one above it. The only thing keeping them separate (not shown in the
>> above context) is an `if (adev->dm.freesync_module)` guard, which can be
>> pulled into the first for_each loop. It would also eliminate a lot of
>> duplicated initialization code.
>>
>> Thoughts?
>>
>> Leo
>>
>
> Ignore what I said, It seems I was looking at the wrong context :) The 
> fact this blob is being done after dc_commit_state() is annoying...
>
> The maintainability of this duplicated logic is a good point. Although 
> I'm not sure if going back to a shared array using custom iterator 
> logic is the best approach. Perhapse we can pull this duplicated logic 
> into a seperate function?

That actually a good idea.

Thanks,
Andrey

>
> Thanks,
> Leo
>
>
>
>>>
>>> Thanks,
>>> Andrey
>>>
>>>>           if (adev->dm.freesync_module)
>>>>               mod_freesync_notify_mode_change(
>>>> -                adev->dm.freesync_module, 
>>>> &dm_new_crtc_state->stream, 1);
>>>> +                adev->dm.freesync_module,
>>>> +                &dm_new_crtc_state->stream, 1);
>>>>           manage_dm_interrupts(adev, acrtc, true);
>>>>       }
>>>
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