Hi, Bibby:
On Fri, 2019-08-30 at 15:38 +0800, Bibby Hsieh wrote:
Moving the driver to atomic helpers regressed cursor responsiveness, because cursor updates need their own atomic commits, which have to be serialized with other commits, that might include fence waits. To avoid this, in certain conditions, we can bypass the atomic helpers for legacy cursor update IOCTLs. Currently the conditions are:
- no asynchronous mode setting commit pending,
- no asynchronous commit that updates the cursor plane is pending.
With the above two conditions met, we know that the manual cursor state update will not conflict with any scheduled update.
Fixes: 119f5173628a ("drm/mediatek: Add DRM Driver for Mediatek SoC MT8173.")
Signed-off-by: Bibby Hsieh bibby.hsieh@mediatek.com Signed-off-by: Daniel Kurtz djkurtz@chromium.org
drivers/gpu/drm/mediatek/mtk_drm_crtc.c | 41 ++++++++++++- drivers/gpu/drm/mediatek/mtk_drm_crtc.h | 2 + drivers/gpu/drm/mediatek/mtk_drm_drv.c | 34 ++++++++++- drivers/gpu/drm/mediatek/mtk_drm_drv.h | 3 + drivers/gpu/drm/mediatek/mtk_drm_plane.c | 73 +++++++++++++++++++++++- 5 files changed, 148 insertions(+), 5 deletions(-)
[snip]
+static int mtk_plane_update(struct drm_plane *plane,
struct drm_crtc *crtc,struct drm_framebuffer *fb,int crtc_x, int crtc_y,unsigned int crtc_w, unsigned int crtc_h,uint32_t src_x, uint32_t src_y,uint32_t src_w, uint32_t src_h,struct drm_modeset_acquire_ctx *ctx)+{
- struct mtk_drm_private *private = plane->dev->dev_private;
- uint32_t crtc_mask = (1 << drm_crtc_index(crtc));
- if (crtc && plane == crtc->cursor &&
plane->state->crtc == crtc &&!(private->commit.flush_for_cursor & crtc_mask))return mtk_plane_cursor_update(plane, crtc, fb,crtc_x, crtc_y, crtc_w, crtc_h,src_x, src_y, src_w, src_h);- return drm_atomic_helper_update_plane(plane, crtc, fb,
crtc_x, crtc_y, crtc_w, crtc_h,src_x, src_y, src_w, src_h, ctx);+}
static const struct drm_plane_funcs mtk_plane_funcs = {
- .update_plane = drm_atomic_helper_update_plane,
- .update_plane = mtk_plane_update,
I think drm core has already process cursor async problem. In [1], you could search 'legacy_cursor_update' and it need driver to implement atomic_async_check() and atomic_async_update() callback function. You could refer to [2] for the implementation.
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/driv... [2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/driv...
Regards, CK
.disable_plane = drm_atomic_helper_disable_plane, .destroy = drm_plane_cleanup, .reset = mtk_plane_reset, @@ -90,7 +154,12 @@ static int mtk_plane_atomic_check(struct drm_plane *plane, if (!state->crtc) return 0;
- crtc_state = drm_atomic_get_crtc_state(state->state, state->crtc);
- if (state->state)
crtc_state = drm_atomic_get_existing_crtc_state(state->state,state->crtc);- else /* Special case for asynchronous cursor updates. */
crtc_state = state->crtc->state;- if (IS_ERR(crtc_state)) return PTR_ERR(crtc_state);