On Tue, 5 Oct 2021 17:16:31 -0300 Igor Matheus Andrade Torrente <igormtorrente@xxxxxxxxx> wrote: > XRGB to ARGB behavior > ================= > During the development, I decided to always fill the alpha channel of > the output pixel whenever the conversion from a format without an alpha > channel to ARGB16161616 is necessary. Therefore, I ignore the value > received from the XRGB and overwrite the value with 0xFFFF. > > My question is, is this behavior acceptable? Hi, that is the expected behaviour. X channel values must never affect anything on screen, hence they must never affect other channels' values. You are free to completely ignore X channel values, and if your output buffer has X channel, then you are free to write (or not write, unless for security reasons) whatever into it. Thanks, pq > > [1] https://lists.freedesktop.org/archives/igt-dev/2021-October/036125.html > > Igor Matheus Andrade Torrente (6): > drm: vkms: Replace the deprecated drm_mode_config_init > drm: vkms: Alloc the compose frame using vzalloc > drm: vkms: Replace hardcoded value of `vkms_composer.map` to > DRM_FORMAT_MAX_PLANES > drm: vkms: Add fb information to `vkms_writeback_job` > drm: vkms: Prepare `vkms_wb_encoder_atomic_check` to accept multiple > formats > drm: vkms: Refactor the plane composer to accept new formats > > drivers/gpu/drm/vkms/vkms_composer.c | 275 ++++++++++++++------------ > drivers/gpu/drm/vkms/vkms_drv.c | 5 +- > drivers/gpu/drm/vkms/vkms_drv.h | 12 +- > drivers/gpu/drm/vkms/vkms_formats.h | 125 ++++++++++++ > drivers/gpu/drm/vkms/vkms_writeback.c | 27 ++- > 5 files changed, 304 insertions(+), 140 deletions(-) > create mode 100644 drivers/gpu/drm/vkms/vkms_formats.h >
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