On reboot, a late DP hot-plug-detect (HPD) IRQ can fire after apps_smmu has already disabled translation for the display subsystem, causing the HPD thread to kick off a new modeset that drives DPU/DP hardware and DMA through a stale IOMMU mapping.
DPU's own .shutdown disables all CRTCs first, but a pending HPD IRQ thread wakes up afterwards, reads the DPCD, and fires an unsolicited hotplug event that triggers a second atomic commit turning the display back on -- right as the IOMMU is disabling translation: systemd-shutdown[1]: Rebooting. msm_dpu: drm_atomic_commit: committing (shutdown disabling CRTCs) arm-smmu 3da0000.iommu: disabling translation msm_dpu: drm_dp_read_dpcd_caps (late HPD IRQ thread wakes up) msm_dpu: drm_sysfs_connector_hotplug_event: DP-1 hotplug event msm_dpu: drm_client_modeset_probe: DP-1 found preferred mode msm_dpu: drm_atomic_commit: committing (unsolicited, re-enables display) dpu_crtc_commit_kickoff: crtc94 first commit arm-smmu 15200000.iommu: disabling translation Mask and flush the IRQ in .shutdown so no HPD event can retrigger a modeset once shutdown has started. Reported on lemans-evk and monaco-evk during reboot stress testing. Assisted-by: Claude:claude-sonnet-5 Signed-off-by: Mahadevan P <[email protected]> --- drivers/gpu/drm/msm/dp/dp_display.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c index dc6f33809ca5..b4fbdeebf952 100644 --- a/drivers/gpu/drm/msm/dp/dp_display.c +++ b/drivers/gpu/drm/msm/dp/dp_display.c @@ -1207,6 +1207,14 @@ static void msm_dp_display_remove(struct platform_device *pdev) platform_set_drvdata(pdev, NULL); } +static void msm_dp_display_shutdown(struct platform_device *pdev) +{ + struct msm_dp_display_private *dp = dev_get_dp_display_private(&pdev->dev); + + disable_irq(dp->irq); + synchronize_irq(dp->irq); +} + static int msm_dp_pm_runtime_suspend(struct device *dev) { struct msm_dp_display_private *dp = dev_get_dp_display_private(dev); @@ -1253,6 +1261,7 @@ static const struct dev_pm_ops msm_dp_pm_ops = { static struct platform_driver msm_dp_display_driver = { .probe = msm_dp_display_probe, .remove = msm_dp_display_remove, + .shutdown = msm_dp_display_shutdown, .driver = { .name = "msm-dp-display", .of_match_table = msm_dp_dt_match, --- base-commit: 1a1757b76427f6201bfe0bf1bea9f7574f332a93 change-id: 20260717-dpshutdown-047912fcf60b Best regards, -- Mahadevan P <[email protected]>
