DALSMC_MSG_...PstateStatus(9)

📦 version 7.3.1, in nixpkgs unstable

💅 DALSMC_MSG_IndicatePstateStatus(9) — aka the "tell PMFW what's up" message

okay so bestie, this one lives in section 9 of the Kernel API Manual, and it's genuinely such a vibe once you get it. The function is DALSMC_MSG_IndicatePstateStatus, and its whole personality is: hey PMFW, here's a rundown of the DMU behaviors we need so UCLK P-state switching can actually happen — like, for example, whether or not the DMU has to modulate refresh rate to pull off those UCLK switches. It's basically a little status report to the power management firmware. 🫶

✨ SYNOPSIS ✨

DALSMC_MSG_IndicatePstateStatus

that's it, that's the whole call. no arguments in the synopsis, no drama. 💅

🎀 DESCRIPTION 🎀

okay so this is a message, right? and it's got a Request side and a Response side. The request is where all the actual tea is — it's a bunch of bit fields, and every single one of them matters, so let's go through them one by one, no skipping, periodt:

  • WaitResp[0] — DAL requires a synchronous response before proceeding. like, it literally cannot move on until it hears back. main character energy fr fr. 😭
  • DrrEnable[1] — DRR (dynamic refresh rate modulation) is active.
  • AltCh[2] — alternate-channel mode is active.
  • AllowUclk[16] — DCN can tolerate UCLK P-state switches. yes queen, allow it. ✨
  • AllowFclk[17] — DCN can tolerate FCLK P-state switches. also iconic.

Response: (none beyond result code)

ngl the response is lowkey doing the absolute bare minimum — you get a result code and that's it. no extra data, no little bonus payload, nothing. and honestly? respect. 🌸

🦋 SEE ALSO 🦋

the kernel file that started it all, bestie:

  • ./drivers/gpu/drm/amd/display/dc/clk_mgr/dcn60/dalsmc.h

and the whole friend group of related messages, all of them, in order, because we don't leave anyone out:

lowkey a whole squad. iykyk. 👑

one last thing bestie 💖 — this page came from ./drivers/gpu/drm/amd/display/... and it's dated October 2026, and it's filed under DALSMC_MSG_...PstateStatus(9). that's the whole footer, bestie, and honestly? slay. go read dalsmc.h and have the day you deserve. 🎀✨🦋

📦 where this page comes from