drm_hwcomposer: Assume premultiplied alpha for CLIENT layer

On db845c, we have seen an odd behavior with modal dialogs in
AOSP, where the background which is normally darkened, was
rendering as black, though it would occasionally flicker to the
right thing. This cropped up after alpha support on planes
landed in 5.15, so we assumed it was an edge case issue with the
dpu1 driver.

But while working on a separate issue seen on x86 hardware:

Roman noticed drm_hwcomposer always sets the blending type to
NONE for the client layer. Which had gone un-noticed becase he
didn't have any devices that exposed the NONE type.

Thus Roman implemented this patch, which sets up the client
blend type to PREMULTIPLIED.

While it did not resolve the x86 issue above, it does resolve
the incorrect rendering seen on db845c with alpha support

Tested-by: Martin Juecker martin.juecker@gmail.com #Exynos 4412
Signed-off-by: Roman Stratiienko <roman.o.stratiienko@globallogic.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Change-Id: I95601c680ca1af0dc9d3b3f102f79f77af081b75
1 file changed
tree: 716ffbc228b486c72c6d8f87ddee2c4a084d30de
  1. .ci/
  2. backend/
  3. bufferinfo/
  4. compositor/
  5. drm/
  6. include/
  7. tests/
  8. utils/
  9. .clang-format
  10. .clang-tidy
  11. .gitlab-ci.yml
  12. Android.bp
  13. DrmHwcTwo.cpp
  14. DrmHwcTwo.h
  16. NOTICE
  17. presubmit.sh
  18. README.md


Patches to drm_hwcomposer are very much welcome, we really want this to be the universal HW composer implementation for Android and similar platforms. So please bring on porting patches, bugfixes, improvements for documentation and new features.

A short list of contribution guidelines:

  • Submit changes via gitlab merge requests on gitlab.freedesktop.org.

  • drm_hwcomposer is Apache 2.0 Licensed and we require contributions to follow the developer's certificate of origin: http://developercertificate.org/.

  • When submitting new code please follow the naming conventions documented in the generated documentation. Also please make full use of all the helpers and convenience macros provided by drm_hwcomposer. The below command can help you with formatting of your patches:

    git diff | clang-format-diff-12 -p 1 -style=file
  • Hardware specific changes should be tested on relevant platforms before committing.

If you need inspiration, please checkout our TODO issues.

Happy hacking!