[PATCH hwc 3/4] drm_hwcomposer: Cleanup gl precompositor init and provide uses_GL flag

[Robert Foss]

This patch is:
Acked-by: Robert Foss <robert.foss at collabora.com>


On 04/26/2018 09:05 PM, John Stultz wrote:
> The drm_hwcomposer has its own GL pre-compositor which is used
> to squish layers when there are more layers then planes on the
> display hardware. In many ways this duplicates the client-side
> GL compositing that is done in SurfaceFlinger, but in theory can
> be more highly optimized for the hardware.
> 
> Unfortunately, due to these optimizations, the drm_hwcomposer's
> pre-compositor becomes somewhat hardware specific (originally
> targeting nvidia hardware, I believe).
> 
> So on some hardware, the gl precompositor may not actually
> initialize due to hardware missing features, or the hardware
> supporting different shader APIs.
> 
> Rather then try to rework the drm_hwcomposers precompositor
> to be more generic, I instead suggest that when the
> precompositor fails to initialize, we simply fall back to the
> already more widely compatible client compositor in
> SurfaceFlinger.
> 
> Thus, this patch cleans up some of the precompositor
> initialization, which didn't handle failures well.
> 
> Cc: Marissa Wall <marissaw at google.com>
> Cc: Sean Paul <seanpaul at google.com>
> Cc: Dmitry Shmidt <dimitrysh at google.com>
> Cc: Robert Foss <robert.foss at collabora.com>
> Cc: Matt Szczesiak <matt.szczesiak at arm.com>
> Cc: Liviu Dudau <Liviu.Dudau at arm.com>
> Cc: David Hanna <david.hanna11 at gmail.com>
> Cc: Rob Herring <rob.herring at linaro.org>
> Cc: Alexandru-Cosmin Gheorghe <Alexandru-Cosmin.Gheorghe at arm.com>
> Cc: Alistair Strachan <astrachan at google.com>
> Reviewed-by: Rob Herring <robh at kernel.org>
> Signed-off-by: John Stultz <john.stultz at linaro.org>
> ---
>   drmdisplaycompositor.cpp | 40 +++++++++++++++++++++-------------------
>   drmdisplaycompositor.h   |  3 +++
>   2 files changed, 24 insertions(+), 19 deletions(-)
> 
> diff --git a/drmdisplaycompositor.cpp b/drmdisplaycompositor.cpp
> index e570923..40af3be 100644
> --- a/drmdisplaycompositor.cpp
> +++ b/drmdisplaycompositor.cpp
> @@ -222,6 +222,13 @@ int DrmDisplayCompositor::Init(DrmResources *drm, int display) {
>       return ret;
>     }
>   
> +  pre_compositor_.reset(new GLWorkerCompositor());
> +  ret = pre_compositor_->Init();
> +  if (ret) {
> +    ALOGE("Failed to initialize OpenGL compositor %d", ret);
> +    pre_compositor_.reset();
> +  }
> +
>     initialized_ = true;
>     return 0;
>   }
> @@ -294,14 +301,16 @@ int DrmDisplayCompositor::ApplySquash(DrmDisplayComposition *display_comp) {
>     }
>   
>     std::vector<DrmCompositionRegion> &regions = display_comp->squash_regions();
> -  ret = pre_compositor_->Composite(display_comp->layers().data(),
> +  if (pre_compositor_) {
> +    ret = pre_compositor_->Composite(display_comp->layers().data(),
>                                      regions.data(), regions.size(), fb.buffer(),
>                                      display_comp->importer());
> -  pre_compositor_->Finish();
> +    pre_compositor_->Finish();
>   
> -  if (ret) {
> -    ALOGE("Failed to squash layers");
> -    return ret;
> +    if (ret) {
> +      ALOGE("Failed to squash layers");
> +      return ret;
> +    }
>     }
>   
>     ret = display_comp->CreateNextTimelineFence();
> @@ -328,14 +337,16 @@ int DrmDisplayCompositor::ApplyPreComposite(
>     }
>   
>     std::vector<DrmCompositionRegion> &regions = display_comp->pre_comp_regions();
> -  ret = pre_compositor_->Composite(display_comp->layers().data(),
> +  if (pre_compositor_) {
> +    ret = pre_compositor_->Composite(display_comp->layers().data(),
>                                      regions.data(), regions.size(), fb.buffer(),
>                                      display_comp->importer());
> -  pre_compositor_->Finish();
> +    pre_compositor_->Finish();
>   
> -  if (ret) {
> -    ALOGE("Failed to pre-composite layers");
> -    return ret;
> +    if (ret) {
> +      ALOGE("Failed to pre-composite layers");
> +      return ret;
> +    }
>     }
>   
>     ret = display_comp->CreateNextTimelineFence();
> @@ -395,15 +406,6 @@ int DrmDisplayCompositor::PrepareFrame(DrmDisplayComposition *display_comp) {
>     std::vector<DrmCompositionRegion> &pre_comp_regions =
>         display_comp->pre_comp_regions();
>   
> -  if (!pre_compositor_) {
> -    pre_compositor_.reset(new GLWorkerCompositor());
> -    int ret = pre_compositor_->Init();
> -    if (ret) {
> -      ALOGE("Failed to initialize OpenGL compositor %d", ret);
> -      return ret;
> -    }
> -  }
> -
>     int squash_layer_index = -1;
>     if (squash_regions.size() > 0) {
>       squash_framebuffer_index_ = (squash_framebuffer_index_ + 1) % 2;
> diff --git a/drmdisplaycompositor.h b/drmdisplaycompositor.h
> index f1965fb..ed6c5f9 100644
> --- a/drmdisplaycompositor.h
> +++ b/drmdisplaycompositor.h
> @@ -98,6 +98,9 @@ class DrmDisplayCompositor {
>       return &squash_state_;
>     }
>   
> +  bool uses_GL() {
> +    return !!pre_compositor_;
> +  }
>    private:
>     struct ModeState {
>       bool needs_modeset = false;
>