Do all mode setting in ast_crtc_helper_mode_set_nofb(), which always runs after disabling the CRTC and before programming the planes. Removes implicit synchronization between the CRTC's atomic disable, enable and the vertical retrace. Display-mode updates require HW cursors to be disabled. The HW cursor only picks up changes at vertical retrace periods. So the CRTC's atomic_disable helper waited for the retrace to delay any following mode-setting operations, which then happened in atomic_enable. See [1] for a description of the problem. With the CRTC helper callback mode_set_nofb, we can now synchronize and reprogram in the same place. As it always runs before the plane update, the plane code can be reordered with the CRTC's later atomic_enable et al. Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx> Link: https://patchwork.freedesktop.org/series/79914/ # 1 --- drivers/gpu/drm/ast/ast_mode.c | 52 ++++++++++++++++++---------------- 1 file changed, 28 insertions(+), 24 deletions(-) diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c index 421fcdad40e4..e8312b3472ed 100644 --- a/drivers/gpu/drm/ast/ast_mode.c +++ b/drivers/gpu/drm/ast/ast_mode.c @@ -1131,6 +1131,33 @@ ast_crtc_helper_mode_valid(struct drm_crtc *crtc, const struct drm_display_mode return status; } +static void ast_crtc_helper_mode_set_nofb(struct drm_crtc *crtc) +{ + struct drm_device *dev = crtc->dev; + struct ast_device *ast = to_ast_device(dev); + struct drm_crtc_state *crtc_state = crtc->state; + struct ast_crtc_state *ast_crtc_state = to_ast_crtc_state(crtc_state); + struct ast_vbios_mode_info *vbios_mode_info = + &ast_crtc_state->vbios_mode_info; + struct drm_display_mode *adjusted_mode = &crtc_state->adjusted_mode; + + /* + * Ensure that no scanout takes place before reprogramming mode + * and format registers. + * + * TODO: Get vblank interrupts working and remove this line. + */ + ast_wait_for_vretrace(ast); + + ast_set_vbios_mode_reg(ast, adjusted_mode, vbios_mode_info); + ast_set_index_reg(ast, AST_IO_VGACRI, 0xa1, 0x06); + ast_set_std_reg(ast, adjusted_mode, vbios_mode_info); + ast_set_crtc_reg(ast, adjusted_mode, vbios_mode_info); + ast_set_dclk_reg(ast, adjusted_mode, vbios_mode_info); + ast_set_crtthd_reg(ast); + ast_set_sync_reg(ast, adjusted_mode, vbios_mode_info); +} + static int ast_crtc_helper_atomic_check(struct drm_crtc *crtc, struct drm_atomic_state *state) { @@ -1207,30 +1234,12 @@ ast_crtc_helper_atomic_flush(struct drm_crtc *crtc, static void ast_crtc_helper_atomic_enable(struct drm_crtc *crtc, struct drm_atomic_state *state) { - struct drm_device *dev = crtc->dev; - struct ast_device *ast = to_ast_device(dev); - struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state, crtc); - struct ast_crtc_state *ast_crtc_state = to_ast_crtc_state(crtc_state); - struct ast_vbios_mode_info *vbios_mode_info = - &ast_crtc_state->vbios_mode_info; - struct drm_display_mode *adjusted_mode = &crtc_state->adjusted_mode; - - ast_set_vbios_mode_reg(ast, adjusted_mode, vbios_mode_info); - ast_set_index_reg(ast, AST_IO_VGACRI, 0xa1, 0x06); - ast_set_std_reg(ast, adjusted_mode, vbios_mode_info); - ast_set_crtc_reg(ast, adjusted_mode, vbios_mode_info); - ast_set_dclk_reg(ast, adjusted_mode, vbios_mode_info); - ast_set_crtthd_reg(ast); - ast_set_sync_reg(ast, adjusted_mode, vbios_mode_info); - ast_crtc_dpms(crtc, DRM_MODE_DPMS_ON); } static void ast_crtc_helper_atomic_disable(struct drm_crtc *crtc, struct drm_atomic_state *state) { struct drm_crtc_state *old_crtc_state = drm_atomic_get_old_crtc_state(state, crtc); - struct drm_device *dev = crtc->dev; - struct ast_device *ast = to_ast_device(dev); ast_crtc_dpms(crtc, DRM_MODE_DPMS_OFF); @@ -1245,16 +1254,11 @@ static void ast_crtc_helper_atomic_disable(struct drm_crtc *crtc, struct drm_ato * simple pageflips on the planes. */ drm_atomic_helper_disable_planes_on_crtc(old_crtc_state, false); - - /* - * Ensure that no scanout takes place before reprogramming mode - * and format registers. - */ - ast_wait_for_vretrace(ast); } static const struct drm_crtc_helper_funcs ast_crtc_helper_funcs = { .mode_valid = ast_crtc_helper_mode_valid, + .mode_set_nofb = ast_crtc_helper_mode_set_nofb, .atomic_check = ast_crtc_helper_atomic_check, .atomic_flush = ast_crtc_helper_atomic_flush, .atomic_enable = ast_crtc_helper_atomic_enable, -- 2.45.2
