Fix DPMS timer not resetting when display activates#233
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kdj0c merged 1 commit intokmscon:mainfrom Jan 18, 2026
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When kmscon starts with the display off/disconnected, the DPMS timer starts counting immediately. When the display later becomes active (via activate_display()), the screen is turned on but the timer is never reset. This causes the timer to expire based on time since kmscon startup rather than time since display activation, leading to unexpected screen blanking shortly after the display becomes active. Fix by calling seat_dpms_reset_timer() in activate_display() after setting DPMS to ON, ensuring the timer starts fresh when a display becomes active. Signed-off-by: Jerome Tollet <[email protected]>
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When kmscon starts with the display off/disconnected, the DPMS timer starts counting immediately. When the display later becomes active (via activate_display()), the screen is turned on but the timer is never reset.
This causes the timer to expire based on time since kmscon startup rather than time since display activation, leading to unexpected screen blanking shortly after the display becomes active.
This PR fixes the issue by calling seat_dpms_reset_timer() in activate_display() after setting DPMS to ON, ensuring the timer starts fresh when a display becomes active.
Changes:
Testing:
Tested on Intel Alder Lake-N with i915 driver. The fix ensures the DPMS timeout is correctly reset when the display becomes active, regardless of whether the display was on or off when kmscon started.