On Sun Jul 5, 2026 at 2:53 AM CST, sashiko-bot wrote: > Thank you for your contribution! Sashiko AI review found 2 potential issue(s) > to consider: > - [High] Hardcoded `possible_crtcs` mask restricts all primary planes to CRTC > 0, breaking multi-display support. > - [High] Direct access of global `plane->state` and `crtc->state` in atomic > commit hooks leads to race conditions and stalled events. > -- > > commit 8a32b307abb3d8e006d032d01a1802aa1e4ae6f0 > Author: Ze Huang <[email protected]> > > drm/xen: replace struct drm_simple_display_pipe with regular atomic helpers > > Replace Xen frontend simple display pipe with explicit plane, CRTC and > encoder objects for each pipeline. Keep generic plane-state validation > before Xen-specific checks, and install GEM framebuffer prepare helper > explicitly. > >> diff --git a/drivers/gpu/drm/xen/xen_drm_front_kms.c >> b/drivers/gpu/drm/xen/xen_drm_front_kms.c >> index 48772b5fe71cf..57e1bef452f83 100644 >> --- a/drivers/gpu/drm/xen/xen_drm_front_kms.c >> +++ b/drivers/gpu/drm/xen/xen_drm_front_kms.c > > [ ... ] > >> @@ -105,17 +105,15 @@ static void send_pending_event(struct >> xen_drm_front_drm_pipeline *pipeline) >> spin_unlock_irqrestore(&dev->event_lock, flags); >> } >> >> -static void display_enable(struct drm_simple_display_pipe *pipe, >> - struct drm_crtc_state *crtc_state, >> - struct drm_plane_state *plane_state) >> +static void xen_drm_crtc_helper_atomic_enable(struct drm_crtc *crtc, >> + struct drm_atomic_commit *state) >> { >> - struct xen_drm_front_drm_pipeline *pipeline = >> - to_xen_drm_pipeline(pipe); >> - struct drm_crtc *crtc = &pipe->crtc; >> + struct xen_drm_front_drm_pipeline *pipeline = to_xen_drm_pipeline(crtc); >> + struct drm_plane_state *plane_state = pipeline->plane.state; > > [Severity: High] > Is it safe to access the global pipeline->plane.state directly here? If > non-blocking commits overlap, this pointer might point to a newer, > uncommitted state. Should this code use drm_atomic_get_new_plane_state() > to extract the state from the drm_atomic_commit object instead? > >> struct drm_framebuffer *fb = plane_state->fb; >> int ret, idx; > > [ ... ] > >> @@ -242,15 +259,19 @@ static int display_check(struct >> drm_simple_display_pipe *pipe, >> return 0; >> } >> >> -static void display_update(struct drm_simple_display_pipe *pipe, >> - struct drm_plane_state *old_plane_state) >> +static void xen_drm_plane_helper_atomic_update(struct drm_plane *plane, >> + struct drm_atomic_commit *state) >> { >> - struct xen_drm_front_drm_pipeline *pipeline = >> - to_xen_drm_pipeline(pipe); >> - struct drm_crtc *crtc = &pipe->crtc; >> + struct drm_plane_state *old_plane_state = >> drm_atomic_get_old_plane_state(state, plane); >> + struct drm_crtc *crtc = plane->state->crtc ?: old_plane_state->crtc; > > [Severity: High] > Can accessing the global plane->state pointer here cause race conditions? > It might be safer to use drm_atomic_get_new_plane_state(state, plane)->crtc > to ensure the correct state is referenced during the atomic commit. > >> + struct xen_drm_front_drm_pipeline *pipeline; >> struct drm_pending_vblank_event *event; >> int idx; >> >> + if (!crtc) >> + return; >> + >> + pipeline = to_xen_drm_pipeline(crtc); >> event = crtc->state->event; > > [Severity: High] > Similarly, does reading and modifying the global crtc->state directly risk > fetching state from a concurrent commit instead of the current one? > >> if (event) { >> struct drm_device *dev = crtc->dev; > > [ ... ] > >> @@ -331,10 +395,37 @@ static int display_pipe_init(struct >> xen_drm_front_drm_info *drm_info, >> >> formats = xen_drm_front_conn_get_formats(&format_count); >> >> - return drm_simple_display_pipe_init(dev, &pipeline->pipe, >> - &display_funcs, formats, >> - format_count, NULL, >> - &pipeline->conn); >> + ret = drm_universal_plane_init(dev, &pipeline->plane, 1, >> + &display_plane_funcs, >> + formats, format_count, >> + NULL, >> + DRM_PLANE_TYPE_PRIMARY, NULL); > > [Severity: High] > Does hardcoding the possible_crtcs mask to 1 restrict all primary planes to > CRTC 0? For pipelines with an index greater than 0, the CRTC might fail to > find a compatible primary plane during atomic validation. Would using > 1 << pipeline->index allow multi-display configurations to work correctly? >
Will change possible_crtcs to 0 to populate automatically. >> + if (ret) >> + return ret;
