[Why] If we're running a headless config with 0 links then the vblank workqueue will be NULL - causing a NULL pointer exception during any commit. [How] Guard access to the workqueue if it's NULL and don't queue or flush work if it is. Cc: Roman Li <Roman.Li@xxxxxxx> Cc: Wayne Lin <Wayne.Lin@xxxxxxx> Cc: Harry Wentland <Harry.Wentland@xxxxxxx> Reported-by: Mike Lothian <mike@xxxxxxxxxxxxxx> BugLink: https://gitlab.freedesktop.org/drm/amd/-/issues/1700 Fixes: 91f86d4cce2 ("drm/amd/display: Use vblank control events for PSR enable/disable") Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@xxxxxxx> --- .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 32 +++++++++++-------- 1 file changed, 18 insertions(+), 14 deletions(-) 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 8837259215d..46e08736f94 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -6185,21 +6185,23 @@ static inline int dm_set_vblank(struct drm_crtc *crtc, bool enable) return 0; #if defined(CONFIG_DRM_AMD_DC_DCN) - work = kzalloc(sizeof(*work), GFP_ATOMIC); - if (!work) - return -ENOMEM; + if (dm->vblank_control_workqueue) { + work = kzalloc(sizeof(*work), GFP_ATOMIC); + if (!work) + return -ENOMEM; - INIT_WORK(&work->work, vblank_control_worker); - work->dm = dm; - work->acrtc = acrtc; - work->enable = enable; + INIT_WORK(&work->work, vblank_control_worker); + work->dm = dm; + work->acrtc = acrtc; + work->enable = enable; - if (acrtc_state->stream) { - dc_stream_retain(acrtc_state->stream); - work->stream = acrtc_state->stream; - } + if (acrtc_state->stream) { + dc_stream_retain(acrtc_state->stream); + work->stream = acrtc_state->stream; + } - queue_work(dm->vblank_control_workqueue, &work->work); + queue_work(dm->vblank_control_workqueue, &work->work); + } #endif return 0; @@ -8809,7 +8811,8 @@ static void amdgpu_dm_commit_planes(struct drm_atomic_state *state, * If PSR or idle optimizations are enabled then flush out * any pending work before hardware programming. */ - flush_workqueue(dm->vblank_control_workqueue); + if (dm->vblank_control_workqueue) + flush_workqueue(dm->vblank_control_workqueue); #endif bundle->stream_update.stream = acrtc_state->stream; @@ -9144,7 +9147,8 @@ static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state) /* if there mode set or reset, disable eDP PSR */ if (mode_set_reset_required) { #if defined(CONFIG_DRM_AMD_DC_DCN) - flush_workqueue(dm->vblank_control_workqueue); + if (dm->vblank_control_workqueue) + flush_workqueue(dm->vblank_control_workqueue); #endif amdgpu_dm_psr_disable_all(dm); } -- 2.25.1
