On Thu, Jan 15, 2026 at 05:34:28PM +0800, Jun Nie wrote: > Dmitry Baryshkov <[email protected]> 于2026年1月15日周四 00:12写道： > > > > On Wed, Jan 14, 2026 at 10:48:17PM +0800, Jun Nie wrote: > > > Jun Nie <[email protected]> 于2025年9月18日周四 21:30写道： > > > > > > > > The content of every half of screen is sent out via one interface in > > > > dual-DSI case. The content for every interface is blended by a LM > > > > pair in quad-pipe case, thus a LM pair should not blend any content > > > > that cross the half of screen in this case. Clip plane into pipes per > > > > left and right half screen ROI if topology is quad pipe case. > > > > > > > > The clipped rectangle on every half of screen is futher handled by two > > > > pipes if its width exceeds a limit for a single pipe. > > > > > > > > Signed-off-by: Jun Nie <[email protected]> > > > > Reviewed-by: Dmitry Baryshkov <[email protected]> > > > > Reviewed-by: Jessica Zhang <[email protected]> > > > > --- > > > > drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c | 11 +++ > > > > drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h | 2 + > > > > drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c | 137 > > > > +++++++++++++++++++++--------- > > > > 3 files changed, 110 insertions(+), 40 deletions(-) > > > > > > > > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c > > > > b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c > > > > index > > > > d825eb8e40ae8bd456ede6269951339e3053d0d3..e925d93b38feac0594d735fdc2c5b9fd5ae83e6a > > > > 100644 > > > > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c > > > > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c > > > > @@ -1604,6 +1604,17 @@ int dpu_crtc_vblank(struct drm_crtc *crtc, bool > > > > en) > > > > return 0; > > > > } > > > > > > > > +/** > > > > + * dpu_crtc_get_num_lm - Get mixer number in this CRTC pipeline > > > > + * @state: Pointer to drm crtc state object > > > > + */ > > > > +unsigned int dpu_crtc_get_num_lm(const struct drm_crtc_state *state) > > > > +{ > > > > + struct dpu_crtc_state *cstate = to_dpu_crtc_state(state); > > > > + > > > > + return cstate->num_mixers; > > > > +} > > > > + > > > > #ifdef CONFIG_DEBUG_FS > > > > static int _dpu_debugfs_status_show(struct seq_file *s, void *data) > > > > { > > > > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h > > > > b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h > > > > index > > > > 94392b9b924546f96e738ae20920cf9afd568e6b..6eaba5696e8e6bd1246a9895c4c8714ca6589b10 > > > > 100644 > > > > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h > > > > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h > > > > @@ -267,4 +267,6 @@ static inline enum dpu_crtc_client_type > > > > dpu_crtc_get_client_type( > > > > > > > > void dpu_crtc_frame_event_cb(struct drm_crtc *crtc, u32 event); > > > > > > > > +unsigned int dpu_crtc_get_num_lm(const struct drm_crtc_state *state); > > > > + > > > > #endif /* _DPU_CRTC_H_ */ > > > > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c > > > > b/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c > > > > index > > > > 5ae58352cbee1251a0140879f04fc7c304cae674..89a5feb6308bcac537562c3dc4e61c16c92e460c > > > > 100644 > > > > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c > > > > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c > > > > @@ -824,8 +824,12 @@ static int dpu_plane_atomic_check_nosspp(struct > > > > drm_plane *plane, > > > > struct dpu_plane_state *pstate = > > > > to_dpu_plane_state(new_plane_state); > > > > struct dpu_sw_pipe_cfg *pipe_cfg; > > > > struct dpu_sw_pipe_cfg *r_pipe_cfg; > > > > + struct dpu_sw_pipe_cfg init_pipe_cfg; > > > > struct drm_rect fb_rect = { 0 }; > > > > + const struct drm_display_mode *mode = > > > > &crtc_state->adjusted_mode; > > > > uint32_t max_linewidth; > > > > + u32 num_lm; > > > > + int stage_id, num_stages; > > > > > > > > min_scale = FRAC_16_16(1, MAX_UPSCALE_RATIO); > > > > max_scale = MAX_DOWNSCALE_RATIO << 16; > > > > @@ -848,13 +852,10 @@ static int dpu_plane_atomic_check_nosspp(struct > > > > drm_plane *plane, > > > > return -EINVAL; > > > > } > > > > > > > > - /* move the assignment here, to ease handling to another pairs > > > > later */ > > > > - pipe_cfg = &pstate->pipe_cfg[0]; > > > > - r_pipe_cfg = &pstate->pipe_cfg[1]; > > > > - /* state->src is 16.16, src_rect is not */ > > > > - drm_rect_fp_to_int(&pipe_cfg->src_rect, &new_plane_state->src); > > > > + num_lm = dpu_crtc_get_num_lm(crtc_state); > > > > > > > > - pipe_cfg->dst_rect = new_plane_state->dst; > > > > + /* state->src is 16.16, src_rect is not */ > > > > + drm_rect_fp_to_int(&init_pipe_cfg.src_rect, > > > > &new_plane_state->src); > > > > > > > > fb_rect.x2 = new_plane_state->fb->width; > > > > fb_rect.y2 = new_plane_state->fb->height; > > > > @@ -879,35 +880,94 @@ static int dpu_plane_atomic_check_nosspp(struct > > > > drm_plane *plane, > > > > > > > > max_linewidth = pdpu->catalog->caps->max_linewidth; > > > > > > > > - drm_rect_rotate(&pipe_cfg->src_rect, > > > > + drm_rect_rotate(&init_pipe_cfg.src_rect, > > > > new_plane_state->fb->width, > > > > new_plane_state->fb->height, > > > > new_plane_state->rotation); > > > > > > > > - if ((drm_rect_width(&pipe_cfg->src_rect) > max_linewidth) || > > > > - _dpu_plane_calc_clk(&crtc_state->adjusted_mode, pipe_cfg) > > > > > max_mdp_clk_rate) { > > > > - if (drm_rect_width(&pipe_cfg->src_rect) > 2 * > > > > max_linewidth) { > > > > - DPU_DEBUG_PLANE(pdpu, "invalid src " > > > > DRM_RECT_FMT " line:%u\n", > > > > - > > > > DRM_RECT_ARG(&pipe_cfg->src_rect), max_linewidth); > > > > - return -E2BIG; > > > > + /* > > > > + * We have 1 mixer pair cfg for 1:1:1 and 2:2:1 topology, 2 > > > > mixer pair > > > > + * configs for left and right half screen in case of 4:4:2 > > > > topology. > > > > + * But we may have 2 rect to split wide plane that exceeds > > > > limit with 1 > > > > + * config for 2:2:1. So need to handle both wide plane > > > > splitting, and > > > > + * two halves of screen splitting for quad-pipe case. Check dest > > > > + * rectangle left/right clipping first, then check wide > > > > rectangle > > > > + * splitting in every half next. > > > > + */ > > > > + num_stages = (num_lm + 1) / 2; > > > > > > Hi Dmitry, > > > Because the plane is checked before crtc is checked in the drm framework. > > > While > > > the topology is decided in crtc check. Thus num_lm is 0 when this > > > function is > > > called for the first time. As a result, the below iteration is not run > > > at all and leads > > > to iommu warning. > > > > How does it lead to IOMMU warnings? > > Because the pipe is not configured with width/height etc when the iteration is > skipped. I have not found the root cause so far. But per the null IOMMU iova > value, suppose it is due to DMA buffer not being prepared when DMA is started.
I'd think, that corresponding SRC regs are either garbage or zero programmed. > > > > > > Do you suggest to change drm framework with adding extra crtc check before > > > plane check, or you prefer the below line here? > > > > > > num_stages = max(1, (num_lm + 1) / 2); > > > > DRM framework provides enough hooks to be able to influence the order or > > operations without changing the framework. But, I'd like to point out > > that for the virtual plane case we already perform plane operations > > from dpu_crtc_atomic_check(). You can employ the same approach. > > Thanks for the suggestion! I see dpu_assign_plane_resources() is called > from crtc side, which avoids the plane splitting before topology decision. > To use this method, it looks like we are enabling the virtual plane by > default. > Because the virtual plane differs from the traditional method only with the > plane splitting and resource preparation. Can we just enable the virtual > plane by default in this situation? In which situation? It is a global switch. And we need to be able to work with it turned off, until corresponding code is dropped. > > Jun > > > > > > > -- > > With best wishes > > Dmitry -- With best wishes Dmitry
