Suspend-To-Ram funciona, mas todos os fãs permanecem

Eu posso suspender a RAM. A tela fica preta e, em seguida, o monitor também entra em economia de energia.

No entanto, quando suspensos, todos os ventiladores do meu sistema permanecem ligados:

• ventilador da CPU
• Ventilador de gabinete
• Ventilador de GPU

log do kernel ao suspender:

[ 1377.806203] PM: suspend entry (s2idle)
[ 1377.809246] Filesystems sync: 0.003 seconds
[ 1377.809249] PM: Preparing system for sleep (s2idle)
[ 1378.070546] Freezing user space processes ... (elapsed 0.003 seconds) done.
[ 1378.073872] OOM killer disabled.
[ 1378.073873] Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done.
[ 1378.075361] PM: Suspending system (s2idle)
[ 1378.075363] printk: Suspending console(s) (use no_console_suspend to debug)
[ 1380.588027] snd_hda_intel 0000:17:00.1: spurious response 0x80000000:0x0, last cmd=0x6f2f00
[ 1380.588031] snd_hda_intel 0000:17:00.1: spurious response 0x80000000:0x0, last cmd=0x6f2f00
[ 1380.588033] snd_hda_intel 0000:17:00.1: spurious response 0x80000000:0x0, last cmd=0x6f2f00
[ 1380.588035] snd_hda_intel 0000:17:00.1: spurious response 0x80000000:0x0, last cmd=0x6f2f00
[ 1380.588037] snd_hda_intel 0000:17:00.1: spurious response 0x80000000:0x0, last cmd=0x6f2f00
[ 1380.588039] snd_hda_intel 0000:17:00.1: spurious response 0x80000000:0x0, last cmd=0x6f2f00
[ 1380.588040] snd_hda_intel 0000:17:00.1: spurious response 0x80000000:0x0, last cmd=0x6f2f00
[ 1380.588042] snd_hda_intel 0000:17:00.1: spurious response 0x80000000:0x0, last cmd=0x6f2f00
[ 1380.588044] snd_hda_intel 0000:17:00.1: spurious response 0x80000000:0x0, last cmd=0x6f2f00
[ 1380.588046] snd_hda_intel 0000:17:00.1: spurious response 0x80000000:0x0, last cmd=0x6f2f00
[ 1382.604016] snd_hda_intel 0000:17:00.1: azx_get_response timeout, switching to polling mode: last cmd=0x006f0900
[ 1383.324019] xpad 1-4:1.0: timed out waiting for output URB to complete, killing
[ 1383.324624] PM: suspend of devices complete after 5248.932 msecs
[ 1383.324629] PM: start suspend of devices complete after 5249.286 msecs
[ 1383.326763] PM: late suspend of devices complete after 2.130 msecs
[ 1383.383948] PM: noirq suspend of devices complete after 56.985 msecs
[ 1383.383951] PM: suspend-to-idle

log do kernel ao acordar:

[ 1399.984106] PM: Timekeeping suspended for 15.947 seconds
[ 1399.984279] PM: resume from suspend-to-idle
[ 1400.044023] PM: noirq resume of devices complete after 59.737 msecs
[ 1400.045312] PM: early resume of devices complete after 1.170 msecs
[ 1400.045645] pci 0000:16:05.0: disabled boot interrupts on device [8086:2034]
[ 1400.045766] pci 0000:64:05.0: disabled boot interrupts on device [8086:2034]
[ 1400.045831] pci 0000:b2:05.0: disabled boot interrupts on device [8086:2034]
[ 1400.212010] snd_hda_intel 0000:17:00.1: azx_get_response timeout, switching to single_cmd mode: last cmd=0x006f0900
[ 1400.212119] azx_single_wait_for_response: 6309 callbacks suppressed
[ 1400.212220] snd_hda_codec_hdmi hdaudioC0D0: HDMI: invalid ELD buf size -1
[ 1400.212522] snd_hda_codec_hdmi hdaudioC0D0: HDMI: invalid ELD buf size -1
[ 1400.212818] snd_hda_codec_hdmi hdaudioC0D0: HDMI: invalid ELD buf size -1
[ 1400.213112] snd_hda_codec_hdmi hdaudioC0D0: HDMI: invalid ELD buf size -1
[ 1400.213407] snd_hda_codec_hdmi hdaudioC0D0: HDMI: invalid ELD buf size -1
[ 1400.213701] snd_hda_codec_hdmi hdaudioC0D0: HDMI: invalid ELD buf size -1
[ 1400.213996] snd_hda_codec_hdmi hdaudioC0D0: HDMI: invalid ELD buf size -1
[ 1400.214291] snd_hda_codec_hdmi hdaudioC0D0: HDMI: invalid ELD buf size -1
[ 1400.292802] nvme nvme0: 16/0/0 default/read/poll queues
[ 1401.944040] pcieport 0000:b2:00.0: pciehp: Timeout on hotplug command 0x07d5 (issued 1960 msec ago)
[ 1401.944044] pcieport 0000:b2:01.0: pciehp: Timeout on hotplug command 0x07d5 (issued 1960 msec ago)
[ 1401.944047] pcieport 0000:b2:03.0: pciehp: Timeout on hotplug command 0x07d5 (issued 1960 msec ago)
[ 1401.944051] pcieport 0000:b2:02.0: pciehp: Timeout on hotplug command 0x07d5 (issued 1960 msec ago)
[ 1401.944114] PM: resume of devices complete after 1898.804 msecs
[ 1401.945342] PM: Finishing wakeup.
[ 1401.945343] OOM killer enabled.
[ 1401.945344] Restarting tasks ... done.
[ 1401.956420] rfkill: input handler enabled
[ 1401.956718] PM: suspend exit
[ 1402.228867] snd_hdac_bus_update_rirb: 430 callbacks suppressed
[ 1402.228874] snd_hda_intel 0000:17:00.1: spurious response 0x80000000:0x0, last cmd=0x6f0900
[ 1402.269012] snd_hda_intel 0000:17:00.1: spurious response 0x0:0x0, last cmd=0x6f0900
[ 1402.285794] rfkill: input handler disabled
[ 1403.352002] snd_hda_intel 0000:17:00.1: spurious response 0x0:0x0, last cmd=0x820000
[ 1403.352037] snd_hda_intel 0000:17:00.1: spurious response 0x0:0x0, last cmd=0x820000
[ 1403.375973] snd_hda_intel 0000:17:00.1: spurious response 0x0:0x0, last cmd=0x1f0500
[ 1403.376011] snd_hda_intel 0000:17:00.1: spurious response 0x233:0x0, last cmd=0x1f0500
[ 1403.449159] snd_hda_intel 0000:17:00.1: spurious response 0x0:0x0, last cmd=0x1f0500
[ 1403.449198] snd_hda_intel 0000:17:00.1: spurious response 0x0:0x0, last cmd=0x4f0015
[ 1403.449239] snd_hda_intel 0000:17:00.1: spurious response 0x3:0x0, last cmd=0x473500
[ 1403.449281] snd_hda_intel 0000:17:00.1: spurious response 0x0:0x0, last cmd=0x470700
[ 1405.084501] igb 0000:04:00.0 eno1: igb: eno1 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX/TX

Verifiquei as configurações do BIOS do Supermicro X11SRM-F, mas não há nenhuma opção de suspensão para ram listada. Além disso, a suspensão parece estar funcionando, apenas sem desligar os ventiladores.

Eu tentei com e sem a opção Extended APIC no BIOS, com o mesmo resultado.

ATUALIZAR:

Parece que o tipo de suspensão que o sistema usa está causando isso.

No log do sistema, afirma que s2idle é usado, que é um sono não muito profundo.

A verificação de outros modos suportados me dá:

$ cat /sys/power/mem_sleep 
[s2idle]

...o que infelizmente significa que outros modos não estão disponíveis. Não está claro qual é o fator limitante, aqui. A placa-mãe? A BIOS?

Do núcleo:

ACPI: (supports S0 S4 S5)

Então, sem S3, isso significa que não há suspensão na RAM?

SO: Ubuntu 20.04.1 LTS

Processador: Xeon W2140B

Placa mãe: Supermicro X11XRM-F