Hi,
  I found a "little" problem with Fibocom WWAN FM350-GL 5G modem in module mtk_t7xx . Power management for this modem is bad. When the notebook goes to sleep/suspend, kernel module mtk_t7xx return an error:

  mtk_t7xx 0000:58:00.0: [PM] SAP suspend error: -110 
  mtk_t7xx 0000:58:00.0: PM: pci_pm_suspend(): t7xx_pci_pm_suspend+0x0/0x20 [mtk_t7xx] returns -110 
  mtk_t7xx 0000:58:00.0: PM: dpm_run_callback(): pci_pm_suspend+0x0/0x1a0 returns -110 
  mtk_t7xx 0000:58:00.0: PM: failed to suspend async: error -110 

  So power management failed to suspend:
  PM: Some devices failed to suspend, or early wake event detected 

  And the notebook not suspend and wake up again.
  It must be this module, because if I remove the module first (modprobe -r), the laptop goes to sleep and wakes up normally.
  However, after reinserting the module, the modem no longer appears in the system.

  Expected state: sleep occurs when the device is put to sleep -
  including the modem. When you wake up, you will wake up, including
  activating the modem and logging into the operator's network.

  Description:    Ubuntu 20.04.5 LTS
  Release:        20.04

  lspci -v:
  58:00.0 Wireless controller [0d40]: MEDIATEK Corp. Device 4d75 (rev 01)
          Subsystem: Device 1cf8:3500
          Flags: bus master, fast devsel, latency 0, IRQ 17
          Memory at 601e800000 (64-bit, prefetchable) [size=32K]
          Memory at 5e800000 (64-bit, non-prefetchable) [size=8M]
          Memory at 601e000000 (64-bit, prefetchable) [size=8M]
          Capabilities: [80] Express Endpoint, MSI 00
          Capabilities: [d0] MSI-X: Enable+ Count=34 Masked-
          Capabilities: [e0] MSI: Enable- Count=1/32 Maskable+ 64bit+
          Capabilities: [f8] Power Management version 3
          Capabilities: [100] Vendor Specific Information: ID=1556 Rev=1 Len=008 <?>
          Capabilities: [108] Latency Tolerance Reporting
          Capabilities: [110] L1 PM Substates
          Capabilities: [200] Advanced Error Reporting
          Capabilities: [300] Secondary PCI Express
          Kernel driver in use: mtk_t7xx
          Kernel modules: mtk_t7xx

  lshw:
  *-generic
                  description: Wireless controller
                  product: MEDIATEK Corp.
                  vendor: MEDIATEK Corp.
                  physical id: 0
                  bus info: pci@0000:58:00.0
                  version: 01
                  width: 64 bits
                  clock: 33MHz
                  capabilities: pciexpress msix msi pm bus_master cap_list
                  configuration: driver=mtk_t7xx latency=0
                  resources: iomemory:600-5ff iomemory:600-5ff irq:17 memory:601e800000-601e807fff memory:5e800000-5effffff memory:601e000000-601e7fffff

  modinfo:
  modinfo mtk_t7xx
  filename:       /lib/modules/5.19.10-051910-generic/kernel/drivers/net/wwan/t7xx/mtk_t7xx.ko
  license:        GPL
  description:    MediaTek PCIe 5G WWAN modem T7xx driver
  author:         MediaTek Inc
  srcversion:     5FA53465EA0167231B632D4
  alias:          pci:v000014C3d00004D75sv*sd*bc*sc*i*
  depends:        
  retpoline:      Y
  intree:         Y
  name:           mtk_t7xx
  vermagic:       5.19.10-051910-generic SMP preempt mod_unload modversions 
  sig_id:         PKCS#7
  signer:         Build time autogenerated kernel key
  sig_key:        7E:38:36:48:BB:F2:74:0E:30:57:1B:6E:64:90:57:55:30:C5:AF:45
  sig_hashalgo:   sha512
  signature:      78:1B:C9:7F:DE:D2:BE:87:EA:17:94:14:C2:51:3E:2C:75:03:76:0F:
                  36:96:92:9B:88:48:B0:C8:73:E6:88:E4:A2:61:25:E9:16:E8:87:40:
                  45:99:CC:50:FD:21:B0:BB:11:0E:B5:8F:CC:5F:47:7A:5E:00:BF:7D:
                  77:50:A1:F5:00:24:DC:EF:E6:3E:A0:3B:0A:D7:2E:84:EC:FC:6B:4D:
                  9E:42:CD:A2:07:C3:D9:F8:6E:7B:76:12:7F:B9:9B:70:6A:22:3D:09:
                  4D:04:98:59:35:2A:95:D1:9A:B3:53:77:BE:E5:3E:50:51:18:D0:CE:
                  9A:DB:3B:0E:DA:4D:05:5D:D1:5F:4F:6B:DB:98:47:F3:32:25:D8:AD:
                  4E:CE:5F:3E:46:76:D9:F4:FA:28:F2:49:B3:3D:D1:5F:74:CF:69:39:
                  D2:B0:64:3D:41:FB:55:1F:AB:D3:76:65:54:C6:06:6E:F7:01:F2:F7:
                  CE:CF:6C:76:17:1B:AD:41:69:29:FB:F8:6B:F9:74:3F:65:6B:C5:63:
                  98:76:D1:69:24:AA:7E:9D:D0:27:BF:AF:0B:C9:30:3C:1B:2A:AB:B9:
                  29:22:D5:6B:16:AB:22:43:16:A0:F6:94:EA:78:E7:54:5F:9B:2D:DA:
                  2E:9B:9F:81:E4:E0:B7:93:ED:9D:8F:79:19:1A:03:2C:00:C5:3A:99:
                  A4:D0:14:6D:21:61:41:02:EC:8D:48:D5:13:0F:D7:AB:5E:B9:BF:17:
                  FA:F3:8C:DE:62:A3:F1:5C:33:9C:FB:72:2F:BF:9F:BD:35:BC:F6:D4:
                  DE:69:68:A7:80:FE:4C:ED:F8:02:97:66:CA:D0:7A:49:4A:A8:D5:C5:
                  67:48:31:42:F9:41:FB:1A:74:52:97:6D:28:A0:2B:03:DA:73:BF:27:
                  0E:84:45:33:40:2D:2F:A9:2C:0D:3A:A5:52:93:1B:E8:6D:27:CD:70:
                  7E:56:CF:0C:8E:C7:6C:E0:A7:16:2A:FF:95:C5:DE:B7:97:D5:FB:92:
                  28:EE:C6:98:1B:D7:06:A3:9D:26:31:09:1E:A8:09:D4:CF:0F:6C:4F:
                  C5:EA:2E:BF:5E:02:02:54:15:A7:A7:86:07:B7:82:3B:C6:68:4A:2F:
                  23:BB:DE:45:3D:52:0E:F2:D8:3B:57:E3:2B:AE:51:2A:E3:D1:DE:B7:
                  F0:40:5A:0E:F4:8C:3F:40:0D:57:05:4C:5F:F3:32:8E:4A:A3:56:69:
                  18:47:8A:F1:91:A2:D6:5F:E9:B3:63:DF:9A:68:0E:F6:37:17:F9:62:
                  D8:50:60:AA:E1:45:1C:3E:FA:23:66:CE:6E:19:1C:B0:51:51:C1:CF:
                  4E:D7:71:24:07:52:7E:7F:F6:78:FF:7E

  
  mmcli -L:
   /org/freedesktop/ModemManager1/Modem/0 [generic] MBIM [14C3:4D75]

mmcli -m 0
  --------------------------------
  General  |                 path: /org/freedesktop/ModemManager1/Modem/0
           |            device id: 82abc72cff5381e11a96d650c8cfdcf1ae4d838e
  --------------------------------
  Hardware |         manufacturer: generic
           |                model: MBIM [14C3:4D75]
           |    firmware revision: 81600.0000.00.29.18.01_VF
           |                       C01
           |         h/w revision: V1.0.6
           |            supported: gsm-umts, lte
           |              current: gsm-umts, lte
           |         equipment id: 862146050381233
  --------------------------------
  System   |               device: /sys/devices/pci0000:00/0000:00:1c.5/0000:58:00.0
           |              drivers: mtk_t7xx
           |               plugin: generic
           |         primary port: wwan0mbim0
           |                ports: wwan0 (net), wwan0at0 (at), wwan0mbim0 (mbim)
  --------------------------------
  Status   |       unlock retries: sim-pin2 (3)
           |                state: registered
           |          power state: on
           |          access tech: lte
           |       signal quality: 51% (recent)
  --------------------------------
  Modes    |            supported: allowed: 3g, 4g; preferred: none
           |              current: allowed: 3g, 4g; preferred: none
  --------------------------------
  IP       |            supported: ipv4, ipv6, ipv4v6

  Any idea?
  Thank you.
  With best regards Jan