[PATCH hwc v2 10/18] drm_hwcomposer: hwcutils: Add function for cloning a DrmHwcLayer

[Alexandru-Cosmin Gheorghe]

On Tue, Apr 17, 2018 at 12:14:14PM -0400, Sean Paul wrote:
> On Wed, Apr 11, 2018 at 04:22:21PM +0100, Alexandru Gheorghe wrote:
> > When doing flattening of a composition on a different CRTC we need to be
> > able to clone a layer in order to import it and then pass it to another CRTC.
> > 
> > Signed-off-by: Alexandru Gheorghe <alexandru-cosmin.gheorghe at arm.com>
> > ---
> >  drmhwcomposer.h |  1 +
> >  hwcutils.cpp    | 11 +++++++++++
> >  2 files changed, 12 insertions(+)
> > 
> > diff --git a/drmhwcomposer.h b/drmhwcomposer.h
> > index f8440fb..b256caf 100644
> > --- a/drmhwcomposer.h
> > +++ b/drmhwcomposer.h
> > @@ -150,6 +150,7 @@ struct DrmHwcLayer {
> >  
> >    int InitFromHwcLayer(hwc_layer_1_t *sf_layer, Importer *importer,
> >                         const gralloc_module_t *gralloc);
> > +  int PopulateFromDrmHwcLayer(DrmHwcLayer *layer);
> >    int ImportBuffer(Importer *importer, const gralloc_module_t *gralloc);
> >  
> >    void SetTransform(int32_t sf_transform);
> > diff --git a/hwcutils.cpp b/hwcutils.cpp
> > index 53a7d82..ff37c3b 100644
> > --- a/hwcutils.cpp
> > +++ b/hwcutils.cpp
> > @@ -149,6 +149,17 @@ int DrmHwcLayer::InitFromHwcLayer(hwc_layer_1_t *sf_layer, Importer *importer,
> >    return ImportBuffer(importer, gralloc);
> >  }
> >  
> > +int DrmHwcLayer::PopulateFromDrmHwcLayer(DrmHwcLayer *src_layer) {
> > +  blending = src_layer->blending;
> > +  sf_handle = src_layer->sf_handle;
> > +  acquire_fence = dup(src_layer->acquire_fence.get());
> 
> Hmm, I think this is the only place where we duplicate a UniqueFd. I _think_
> this will be Ok, but do you need to use this? Could you instead defer trying to
> flatten if the original acquire_fence hasn't fired? Also, you don't check the
> return value.

Thinking about it, I don't think there is any way we could try
flattening, without acquire_fence being already fired.

> 
> > +  display_frame = src_layer->display_frame;
> > +  alpha = src_layer->alpha;
> > +  source_crop = src_layer->source_crop;
> > +  transform = src_layer->transform;
> 
> It also doesn't seem like you're populating all of the fields so the function
> name is misleading.
> 

Which one are you referring to? This follows the properties copied by
HwcLayer::PopulateDrmLayer which I assume was correct.

> 
> > +  return 0;
> > +}
> > +
> >  int DrmHwcLayer::ImportBuffer(Importer *importer,
> >                                const gralloc_module_t *gralloc) {
> >    int ret = buffer.ImportBuffer(sf_handle, importer);
> > -- 
> > 2.7.4
> > 
> 
> -- 
> Sean Paul, Software Engineer, Google / Chromium OS

-- 
Cheers,
Alex G