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

[Leo]

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

> 
> 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);
>>       }
>