Jun Nie <[email protected]> 于2026年9月3日周四 22:30写道： > > There is a spurious timeout error message under the following reproduction > steps: > 1. Run "modetest -M msm -r" and press CTRL+Z to pause it. > 2. Run "while true; do rtcwake -m mem -s 3 -v; sleep 2; done" > > Resulting error message: > [ 124.018206] [drm:dpu_encoder_virt_atomic_disable:1425] [dpu error]enc35 > timeout pending > > dpu_crtc_commit_kickoff() calls dpu_encoder_kickoff() to set frame busy > bits, and then arms the frame done timer. If the frame done IRQ fires > between these two steps, the IRQ handler clears the busy bits before the > timer is armed. As a result, the timer runs with busy bits already cleared > and is never cancelled by subsequent IRQ handlers, leading to a false > timeout warning. > > Delete the pending timer when all busy bits are cleared in the frame done > callback to prevent false timeouts. >
Another option is to wrap the enc_spinlock lock/unlock pair in dpu_encoder.c and expose it to dpu_crtc.c to make the sequence of dpu_encoder_kickoff() and dpu_encoder_start_frame_done_timer() atomic against the IRQ handler. However, this breaks encoder self-containment to some extent. Furthermore, initial testing revealed a deadlock involving additional locks beyond dpu_enc->enc_spinlock. - Jun
