FROMLIST: drm/msm/dp: add .shutdown to mask HPD IRQ before system shutdown#842
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FROMLIST: drm/msm/dp: add .shutdown to mask HPD IRQ before system shutdown#842yashgupta2126 wants to merge 1 commit into
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…tdown 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. Link: https://lore.kernel.org/all/20260717-dpshutdown-v1-1-b062c2f7dfb1@oss.qualcomm.com/ Assisted-by: Claude:claude-sonnet-5 Signed-off-by: Mahadevan P <mahadevan.p@oss.qualcomm.com> Signed-off-by: Yash Gupta <yash.gupta@oss.qualcomm.com>
yashgupta2126
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Nicolas Dechesne (ndechesne),
Kaushal Kumar (quic-kaushalk) and
Tingwei Zhang (quic-tingweiz)
July 20, 2026 06:18
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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.
Link: https://lore.kernel.org/all/20260717-dpshutdown-v1-1-b062c2f7dfb1@oss.qualcomm.com/
CRs-Fixed: 4573119