[PATCH 56/73] drm/amd/display: Remove dangling planes on dc commit state

[Leo Li]

On 2017-11-10 02:00 PM, Andrey Grodzovsky wrote:
> 
> 
> On 11/09/2017 03:05 PM, Harry Wentland wrote:
>> From: "Leo (Sunpeng) Li" <sunpeng.li at amd.com>
>>
>> When disabling pipe splitting, we need to make sure we disable both
>> planes used.
>>
>> This should be done for Linux as well.
>>
>> Change-Id: I79f5416a55bd26c19ca3cfb346a943d69872a8ce
>> Signed-off-by: Leo (Sunpeng) Li <sunpeng.li at amd.com>
>> Reviewed-by: Tony Cheng <Tony.Cheng at amd.com>
>> Acked-by: Harry Wentland <harry.wentland at amd.com>
>> ---
>>   drivers/gpu/drm/amd/display/dc/core/dc.c | 39 
>> ++++++++++++++++++++++++++++----
>>   1 file changed, 35 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/display/dc/core/dc.c 
>> b/drivers/gpu/drm/amd/display/dc/core/dc.c
>> index 56df1304e49c..d70dbc102123 100644
>> --- a/drivers/gpu/drm/amd/display/dc/core/dc.c
>> +++ b/drivers/gpu/drm/amd/display/dc/core/dc.c
>> @@ -629,6 +629,39 @@ static bool construct(struct dc *dc,
>>       return false;
>>   }
>> +static void disable_dangling_plane(struct dc *dc, struct dc_state 
>> *context)
>> +{
>> +    int i, j;
>> +    struct dc_state *dangling_context = dc_create_state();
>> +    struct dc_state *current_ctx;
>> +
>> +    if (dangling_context == NULL)
>> +        return;
>> +
>> +    dc_resource_state_copy_construct(dc->current_state, 
>> dangling_context);
>> +
>> +    for (i = 0; i < dc->res_pool->pipe_count; i++) {
>> +        struct dc_stream_state *old_stream =
>> +                dc->current_state->res_ctx.pipe_ctx[i].stream;
>> +        bool should_disable = true;
>> +
>> +        for (j = 0; j < context->stream_count; j++) {
>> +            if (old_stream == context->streams[j]) {
>> +                should_disable = false;
>> +                break;
>> +            }
>> +        }
>> +        if (should_disable && old_stream) {
>> +            dc_rem_all_planes_for_stream(dc, old_stream, 
>> dangling_context);
> 
> Why this is not happening in atomic_check during dm_update_planes_state 
> with enable set to false ? Since the old stream is present
> I assume old crtc_state for planes to disable is present and as I see 
> from the code it should happen in that function
> 
> Thanks,
> Andrey
You're correct, the above logic should be done in atomic check. However,
the apply_ctx_for_surface call below is the reason why this code (or
rather, this entire function) is here.

Due to some refactoring efforts that rearranged the front-end and
back-end programming sequence, the logic for disabling surfaces for
streams have been moved here. disable_dangling_planes is responsible for
disabling the front end of streams that do not exist in the new dc_state
(i.e. streams that are disabled). See one of the relevant patches here:
https://lists.freedesktop.org/archives/amd-gfx/2017-October/015201.html

This cannot be done in atomic check, because there is currently no
support in DC to explicitly mark a stream or surface as disabled. We
infer it by comparing the current and new dc_states, then call apply_ctx
to program it.

Leo

> 
>> +            dc->hwss.apply_ctx_for_surface(dc, old_stream, 0, 
>> dangling_context);
>> +        }
>> +    }
>> +
>> +    current_ctx = dc->current_state;
>> +    dc->current_state = dangling_context;
>> +    dc_release_state(current_ctx);
>> +}
>> +
>>   
>> /******************************************************************************* 
>>
>>    * Public functions
>>    
>> ******************************************************************************/ 
>>
>> @@ -833,14 +866,14 @@ static enum dc_status 
>> dc_commit_state_no_check(struct dc *dc, struct dc_state *c
>>       int i, k, l;
>>       struct dc_stream_state *dc_streams[MAX_STREAMS] = {0};
>> +    disable_dangling_plane(dc, context);
>> +
>>       for (i = 0; i < context->stream_count; i++)
>>           dc_streams[i] =  context->streams[i];
>>       if (!dcb->funcs->is_accelerated_mode(dcb))
>>           dc->hwss.enable_accelerated_mode(dc);
>> -
>> -
>>       for (i = 0; i < context->stream_count; i++) {
>>           const struct dc_sink *sink = context->streams[i]->sink;
>> @@ -864,8 +897,6 @@ static enum dc_status 
>> dc_commit_state_no_check(struct dc *dc, struct dc_state *c
>>               }
>>           }
>> -
>> -
>>           CONN_MSG_MODE(sink->link, "{%dx%d, %dx%d@%dKhz}",
>>                   context->streams[i]->timing.h_addressable,
>>                   context->streams[i]->timing.v_addressable,
>