Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
Pre-existing issues: - [High] The function `amdgpu_dm_atomic_commit_tail` uses `kzalloc` with `GFP_KERNEL` and acquires a `mutex`, both of which can sleep, despite being an atomic commit path. - [High] AMDGPU never updates the privacy screen hardware state because privacy screen updates force a modeset, but the commit tail skips privacy screen updates during modesets. -- --- Patch [1]: [PATCH 1/2] drm/amd/display: Skip connector updates without a stream --- commit 3a3a91e5bab6bdb82ebcebf89c73cd8b740ca904 Author: David Weber <[email protected]> drm/amd/display: Skip connector updates without a stream Atomic DPMS can leave a connector assigned to an enabled but inactive CRTC after the driver has removed its DC stream. A later atomic commit can then change HDR_OUTPUT_METADATA or Broadcast RGB while leaving the CRTC mode, routing and active state unchanged. This patch skips stream updates until a stream exists, preventing null pointer dereferences when the connector stream-update path is reached with a NULL stream. > diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c > b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c > index 567bf04979ee5..712e8d3e0a01d 100644 > --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c > +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c > @@ -5050,6 +5050,9 @@ static void amdgpu_dm_atomic_commit_tail(struct > drm_atomic_commit *state) > > dm_new_crtc_state = to_dm_crtc_state(new_crtc_state); > dm_old_crtc_state = to_dm_crtc_state(old_crtc_state); [Severity: High] This isn't a bug introduced by this patch, but does this skip logic prevent privacy screen updates? In amdgpu_dm_connector_atomic_check(), any change to the privacy screen software state forces a modeset: new_crtc_state->mode_changed = true; However, earlier in this loop in amdgpu_dm_atomic_commit_tail(), connectors undergoing a modeset are skipped: /* Skip any modesets/resets */ if (!acrtc || drm_atomic_crtc_needs_modeset(new_crtc_state)) continue; Since the only call to update the privacy screen hardware is located at the very end of this loop: drm_connector_update_privacy_screen(new_con_state); Will this cause privacy screen updates to be permanently skipped because they force a modeset that bypasses the update code? > + /* DPMS-off leaves the connector routed to a streamless CRTC. */ > + if (!dm_new_crtc_state->stream) > + continue; > > scaling_changed = is_scaling_state_different(dm_new_con_state, > dm_old_con_state); [Severity: High] This is a pre-existing issue, but are there sleeping functions called from this atomic context? Later in amdgpu_dm_atomic_commit_tail(), kzalloc is called with GFP_KERNEL: dummy_updates = kzalloc(sizeof(struct dc_surface_update) * MAX_SURFACES, GFP_KERNEL); And then a mutex is acquired: mutex_lock(&dm->dc_lock); Since drm_atomic_helper_commit_tail() and its variants execute in an atomic context where sleeping is forbidden, could this kzalloc(..., GFP_KERNEL) and mutex_lock() cause kernel warnings, system instability, or potential deadlocks? Also, if the memory allocation fails, the subsequent hardware programming in dc_update_planes_and_stream() is silently skipped. Can this lead to an unrecoverable state mismatch since commit_tail cannot return error codes? -- Sashiko AI review ยท https://sashiko.dev/#/patchset/[email protected]?part=1
