This command:
echo -n powersave > /sys/module/pcie_aspm/parameters/policy
Allowed to enable L1 for AST1150 and now basically all my PCIe devices should support L1 (thanks to man from this thread):
# lspci -vv | awk '/ASPM/{print $0}' RS= | grep --color -P '(^[a-z0-9:.]+|ASPM )'
00:06.0 PCI bridge: Intel Corporation Raptor Lake PCIe 4.0 Graphics Port (rev 01) (prog-if 00 [Normal decode])
LnkCap: Port #5, Speed 16GT/s, Width x4, ASPM L1, Exit Latency L1 <16us
LnkCtl: ASPM L1 Enabled; RCB 64 bytes, Disabled- CommClk+
00:1a.0 PCI bridge: Intel Corporation Alder Lake-S PCH PCI Express Root Port #25 (rev 11) (prog-if 00 [Normal decode])
LnkCap: Port #25, Speed 16GT/s, Width x4, ASPM L1, Exit Latency L1 <64us
LnkCtl: ASPM L1 Enabled; RCB 64 bytes, Disabled- CommClk+
00:1b.0 PCI bridge: Intel Corporation Device 7ac0 (rev 11) (prog-if 00 [Normal decode])
LnkCap: Port #17, Speed 8GT/s, Width x4, ASPM L1, Exit Latency L1 <64us
LnkCtl: ASPM L1 Enabled; RCB 64 bytes, Disabled- CommClk-
00:1c.0 PCI bridge: Intel Corporation Alder Lake-S PCH PCI Express Root Port #1 (rev 11) (prog-if 00 [Normal decode])
LnkCap: Port #1, Speed 8GT/s, Width x4, ASPM L1, Exit Latency L1 <64us
LnkCtl: ASPM L1 Enabled; RCB 64 bytes, Disabled- CommClk+
00:1c.4 PCI bridge: Intel Corporation Alder Lake-S PCH PCI Express Root Port #5 (rev 11) (prog-if 00 [Normal decode])
LnkCap: Port #5, Speed 8GT/s, Width x1, ASPM L1, Exit Latency L1 <64us
LnkCtl: ASPM L1 Enabled; RCB 64 bytes, Disabled- CommClk-
00:1c.7 PCI bridge: Intel Corporation Alder Lake-S PCH PCI Express Root Port #8 (rev 11) (prog-if 00 [Normal decode])
LnkCap: Port #8, Speed 8GT/s, Width x1, ASPM L1, Exit Latency L1 <64us
LnkCtl: ASPM L1 Enabled; RCB 64 bytes, Disabled- CommClk+
00:1d.0 PCI bridge: Intel Corporation Alder Lake-S PCH PCI Express Root Port #9 (rev 11) (prog-if 00 [Normal decode])
LnkCap: Port #9, Speed 8GT/s, Width x4, ASPM L1, Exit Latency L1 <64us
LnkCtl: ASPM L1 Enabled; RCB 64 bytes, Disabled- CommClk-
01:00.0 Non-Volatile memory controller: Kingston Technology Company, Inc. DC2000B NVMe SSD E18DC (rev 01) (prog-if 02 [NVM Express])
LnkCap: Port #0, Speed 16GT/s, Width x4, ASPM L1, Exit Latency L1 <64us
LnkCtl: ASPM L1 Enabled; RCB 64 bytes, Disabled- CommClk+
02:00.0 Non-Volatile memory controller: Kingston Technology Company, Inc. DC2000B NVMe SSD E18DC (rev 01) (prog-if 02 [NVM Express])
LnkCap: Port #0, Speed 16GT/s, Width x4, ASPM L1, Exit Latency L1 <64us
LnkCtl: ASPM L1 Enabled; RCB 64 bytes, Disabled- CommClk+
04:00.0 Ethernet controller: Intel Corporation Ethernet Controller X550 (rev 01)
LnkCap: Port #0, Speed 8GT/s, Width x4, ASPM L0s L1, Exit Latency L0s <2us, L1 <16us
LnkCtl: ASPM L1 Enabled; RCB 64 bytes, Disabled- CommClk+
04:00.1 Ethernet controller: Intel Corporation Ethernet Controller X550 (rev 01)
LnkCap: Port #0, Speed 8GT/s, Width x4, ASPM L0s L1, Exit Latency L0s <2us, L1 <16us
LnkCtl: ASPM L1 Enabled; RCB 64 bytes, Disabled- CommClk+
06:00.0 PCI bridge: ASRock Incorporation Device 1150 (rev 06) (prog-if 00 [Normal decode])
LnkCap: Port #0, Speed 5GT/s, Width x1, ASPM L0s L1, Exit Latency L0s <512ns, L1 <32us
LnkCtl: ASPM L1 Enabled; RCB 64 bytes, Disabled- CommClk+
But system still not able to go below pkg C2.