** Description changed: [Impact] On Dell systems (CID: 202511-38076), the internal OLED display drops to a visibly lower refresh rate after suspend/resume. The state persists until a cold reboot. Applications like glmark2 still report rendering at 120Hz but the panel visually operates at a much lower frame rate. Steps to reproduce: 1. Unplug all accessories 2. Boot into OS 3. Drag a window around the desktop and observe the FPS (smooth 120Hz) 4. Suspend then resume 5. Drag a window around the desktop — FPS is now visibly and permanently lower Failure rate: 100% on affected hardware Affected test case: com.canonical.certification::suspend/display_after_suspend Root cause: The i915 driver initializes Panel Replay (an OLED power-saving feature) via DPCD negotiation during resume. On this specific panel, Panel Replay causes the display to be locked at a degraded frame rate after resume. The panel does not correctly handle Panel Replay activation in this configuration, resulting in permanently reduced FPS until a cold reboot. [Fix] Add a new quirk QUIRK_DISABLE_PANEL_REPLAY to the Intel i915 display driver that prevents Panel Replay DPCD initialization for problematic panel setups. Apply this quirk for Dell systems with device ID 0xb080, subsystem vendor 0x1028, subsystem device 0x0db9, and sink OUI 0x00:0x22:0xb9. When the quirk is present, _panel_replay_init_dpcd() returns early before reading Panel Replay capability from the panel's DPCD registers, effectively disabling the Panel Replay feature for this hardware combination. The patch is currently under review in the Intel DRM/i915 mailing list: https://patchwork.freedesktop.org/series/163265/ Upstream issue tracker: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/7521 + In linux-next + 1de647abdfda9 drm/i915/psr: Fixes for Dell XPS DA14260 quirk + 45c77d4bf8d4d drm/i915/psr: Disable Panel Replay on Dell XPS 14 DA14260 as a quirk + [Test Plan] On a Dell system (CID: 202511-38076) with Intel integrated graphics: 1. Suspend and resume the system: - $ sudo rtcwake -m mem -s 20 + $ sudo rtcwake -m mem -s 20 2. After resume, drag a window around the desktop and observe the frame rate. Without the patch: The display FPS drops permanently after resume and stays degraded until cold reboot. With the patch: The display maintains normal 120Hz refresh rate after suspend/resume. [Where problems could occur] It may break Panel Replay functionality on Intel i915 display configurations. The quirk check is inserted early in _panel_replay_init_dpcd(), before any DPCD reads occur. If the quirk match logic incorrectly identifies a panel (e.g., due to incorrect OUI or PCI subsystem ID matching), Panel Replay will be silently disabled on panels where it would otherwise work correctly. This would cause affected systems to lose the power-saving benefits of Panel Replay without any visible error — users would see slightly higher power consumption on OLED panels. Additionally, if the quirk infrastructure itself has a bug (e.g., the intel_has_dpcd_quirk() function returning unexpected values), it could either fail to disable Panel Replay on affected hardware (regression still present) or disable it too broadly on unaffected hardware. [Other Info] The patch is under review in the Intel DRM mailing list (patchwork series 163265) and has not yet landed in the mainline kernel.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2144712 Title: On Dell system, the internal OLED display drops to a visibly low FPS after suspend/resume To manage notifications about this bug go to: https://bugs.launchpad.net/hwe-next/+bug/2144712/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
