Re: [PATCH v2 0/5] drm: rockchip: various ports for older VOPs

From: Alex Bee
Date: Sat Jul 25 2020 - 09:52:40 EST

Am 22.07.20 um 23:43 schrieb Daniel Vetter:
On Wed, Jul 22, 2020 at 8:13 PM Alex Bee <knaerzche@xxxxxxxxx> wrote:

this series mainly ports existining functionality to older SoCs - most
importantly enables alpha blending for RK3036, RK3066, RK3126 and
Besides that, it also changes the window type from DRM_PLANE_TYPE_CURSOR
to DRM_PLANE_TYPE_OVERLAY for VOPs that have only one (1) overlay window.
This doesn't make much sense, the cursor overlay is really just a hint
for legacy ioctls that this is the overlay that should be used for
cursors. Compositors should try to use such planes as full overlays
(if they don't want to use them as a cursor). So sounds like a case of
"fix your compositor".
I agree here - but: If HWC windows would have been implemented in this particular driver, their max size would be 128x128 on some SoCs - so they woudn't be really suitable to create an OSD overlay at 4K, for example. I don't know, but I guess other vendors implement their HWC windows on this reduced HW resources as well. I guess that is one of the reasons, why userspace, which aims to be cross-plattfrom, avoids DRM_PLANE_TYPE_CURSOR when its looking for an usable overlay plane. (a heuristic, indeed)
For atomic there's 0 difference between a overlay or a cursor (primary
plane is still treated somewhat special in the RMFB ioctl, but again
that's for backwards compat reasons with existing uapi, not because
the primary plane is different).

What does happen though is that this breaks cursor for legacy
userspace, which is probably not really what you want.

Indeed not.

Beforhand I was submiiting this, I looked arround and couldn't find anything which relies or even depends of a cursor window to be available. Even if: as per spec only one DRM_PLANE_TYPE_PRIMARY is mandatory, everything else is optional.



Changes in v2:
- drop not yet upstreamed dsp_data_swap from RK3188 regs
- rephrase most commit messages

Alex Bee (5):
drm: rockchip: add scaling for RK3036 win1
drm: rockchip: add missing registers for RK3188
drm: rockchip: add alpha support for RK3036, RK3066, RK3126 and RK3188
drm: rockchip: set alpha_en to 0 if it is not used
drm: rockchip: use overlay windows as such

drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 1 +
drivers/gpu/drm/rockchip/rockchip_vop_reg.c | 42 ++++++++++++++++++---
drivers/gpu/drm/rockchip/rockchip_vop_reg.h | 1 +
3 files changed, 38 insertions(+), 6 deletions(-)


Daniel Vetter
Software Engineer, Intel Corporation

Best Regards