Comment 17 for bug 1759950

This seems to be the crux of the issue. In a VT console I did:

DISPLAY=:0 XFSETTINGSD_DEBUG=1 xfsettingsd --replace --no-daemon

and the did the usual lid-close->resume cycle and found:

xfce4-settings(displays): UPower lid event received (open -> closed).
xfce4-settings(displays): Toggling internal output LVDS.
xfce4-settings(displays): CRTC 79 assigned to LVDS.
xfce4-settings(displays): LVDS will be disabled.
xfce4-settings(displays): CRTC 79 must be temporarily disabled.
xfce4-settings(displays): Disabling CRTC 79.
xfce4-settings(displays): min_h = 200, min_w = 320, max_h = 4096, max_w = 4096, prev_h = 800, prev_w = 1280, prev_hmm = 211, prev_wmm = 338, h = 0, w = 0, hmm = 0, wmm = 0.
xfce4-settings(displays): Configuring CRTC 79.
xfce4-settings(displays): Configuring CRTC 80.
xfce4-settings(displays): RRScreenChangeNotify event received.
xfce4-settings(displays): Refreshing RandR cache.
xfce4-settings(displays): Detected CRTC 79.
xfce4-settings(displays): Detected CRTC 80.
xfce4-settings(displays): Detected output 82 LVDS.
xfce4-settings(displays): Noutput: before = 1, after = 1.
xfce4-settings(displays): RRScreenChangeNotify event received.
xfce4-settings(displays): Refreshing RandR cache.
xfce4-settings(displays): Detected CRTC 79.
xfce4-settings(displays): Detected CRTC 80.
xfce4-settings(displays): Detected output 82 LVDS.
xfce4-settings(displays): Noutput: before = 1, after = 1.
xfce4-settings(displays): UPower lid event received (closed -> open).
xfce4-settings(displays): Toggling internal output LVDS.
xfce4-settings(displays): CRTC 79 assigned to LVDS.
xfce4-settings(displays): CRTC 79, output list[0] -> 82.
xfce4-settings(displays): LVDS will be re-enabled.
xfce4-settings(displays): Normalized CRTC 79: size=1280x800, pos=0x0.
xfce4-settings(displays): min_h = 200, min_w = 320, max_h = 4096, max_w = 4096, prev_h = 800, prev_w = 1280, prev_hmm = 211, prev_wmm = 338, h = 0, w = 0, hmm = 0, wmm = 0.
xfce4-settings(displays): Configuring CRTC 79.
xfce4-settings(displays): Applying changes to CRTC 79.
xfce4-settings(displays): Applying CRTC 79 Transform: x=0.000000 y=0.000000, filter=bilinear.

(xfsettingsd:5453): xfsettingsd-WARNING **: 13:34:57.316: Failed to configure CRTC 79.
xfce4-settings(displays): Configuring CRTC 80.

(xfsettingsd:5453): xfsettingsd-CRITICAL **: 13:34:57.316: Failed to apply display settings

The matching kernel log messages:

2019-06-18T13:34:57.262508+0100 Asus-F5-01 kernel: CPU1 is up
2019-06-18T13:34:57.262606+0100 Asus-F5-01 kernel: ACPI: Waking up from system sleep state S3
2019-06-18T13:34:57.262697+0100 Asus-F5-01 kernel: ACPI: EC: interrupt unblocked
2019-06-18T13:34:57.262797+0100 Asus-F5-01 kernel: ahci 0000:00:12.0: set SATA to AHCI mode
2019-06-18T13:34:57.263390+0100 Asus-F5-01 kernel: ACPI: EC: event unblocked
2019-06-18T13:34:57.263864+0100 Asus-F5-01 kernel: sd 0:0:0:0: [sda] Starting disk
2019-06-18T13:34:57.264614+0100 Asus-F5-01 kernel: [drm] radeon: 1 quad pipes, 1 z pipes initialized.
2019-06-18T13:34:57.264731+0100 Asus-F5-01 kernel: [drm] PCIE GART of 512M enabled (table at 0x0000000034880000).
2019-06-18T13:34:57.265160+0100 Asus-F5-01 kernel: radeon 0000:01:05.0: WB enabled
2019-06-18T13:34:57.266060+0100 Asus-F5-01 kernel: radeon 0000:01:05.0: fence driver on ring 0 use gpu addr 0x0000000080000000 and cpu addr 0x0000000090ce6220
2019-06-18T13:34:57.266622+0100 Asus-F5-01 kernel: [drm] radeon: ring at 0x0000000080001000
2019-06-18T13:34:57.266724+0100 Asus-F5-01 kernel: [drm] ring test succeeded in 2 usecs
2019-06-18T13:34:57.266822+0100 Asus-F5-01 kernel: [drm] ib test succeeded in 0 usecs
2019-06-18T13:34:57.267127+0100 Asus-F5-01 kernel: ata5.00: ACPI cmd ef/03:0c:00:00:00:a0 (SET FEATURES) filtered out
2019-06-18T13:34:57.267248+0100 Asus-F5-01 kernel: ata5.00: ACPI cmd ef/03:42:00:00:00:a0 (SET FEATURES) filtered out
2019-06-18T13:34:57.267532+0100 Asus-F5-01 kernel: ata5.00: ACPI cmd f5/00:00:00:00:00:a0 (SECURITY FREEZE LOCK) filtered out
2019-06-18T13:34:57.267627+0100 Asus-F5-01 kernel: OOM killer enabled.
2019-06-18T13:34:57.267721+0100 Asus-F5-01 kernel: Restarting tasks ... done.
2019-06-18T13:34:57.249139+0100 Asus-F5-01 systemd-logind[767]: Lid opened.
2019-06-18T13:34:57.252622+0100 Asus-F5-01 wpa_supplicant[818]: wlp2s0: CTRL-EVENT-DISCONNECTED bssid=28:28:5d:07:76:09 reason=3 locally_generated=1
2019-06-18T13:34:57.253272+0100 Asus-F5-01 wpa_supplicant[818]: wlp2s0: CTRL-EVENT-REGDOM-CHANGE init=CORE type=WORLD
2019-06-18T13:34:57.277517+0100 Asus-F5-01 NetworkManager[812]: <warn> [1560861297.2774] sup-iface[0x55757fb47af0,wlp2s0]: connection disconnected (reason -3)
2019-06-18T13:34:57.277716+0100 Asus-F5-01 NetworkManager[812]: <info> [1560861297.2776] device (wlp2s0): supplicant interface state: completed -> disconnected

(xfsettingsd:5453): xfsettingsd-WARNING **: 13:34:57.316: Failed to configure CRTC 79.
xfce4-settings(displays): Configuring CRTC 80.

(xfsettingsd:5453): xfsettingsd-CRITICAL **: 13:34:57.316: Failed to apply display settings

2019-06-18T13:34:57.344993+0100 Asus-F5-01 kernel: video LNXVIDEO:00: Restoring backlight state
2019-06-18T13:34:57.345816+0100 Asus-F5-01 systemd-sleep[5464]: System resumed.
2019-06-18T13:34:57.349621+0100 Asus-F5-01 kernel: ata3: SATA link down (SStatus 0 SControl 300)
2019-06-18T13:34:57.349831+0100 Asus-F5-01 kernel: PM: suspend exit