drm_dp_read_dpcd_caps(9)

📦 version 7.3.1, in nixpkgs unstable

🎀 drm_dp_read_dpcd_caps(9) 🎀

okay so this little icon is straight out of the Kernel API Manual, and bestie, it’s giving “read the DisplayPort tea and report back” energy. 💅✨

🌸 NAME 🌸

drm_dp_read_dpcd_caps — read DPCD caps and extended DPCD caps if available

🦋 SYNOPSIS 🦋

int drm_dp_read_dpcd_caps (struct drm_dp_aux *aux , u8
       dpcd[DP_RECEIVER_CAP_SIZE] );

🎀 ARGUMENTS 🎀

  • aux — the DisplayPort AUX channel 💖
  • dpcd — the buffer where the resulting DPCD gets stored 🫶

✨ DESCRIPTION ✨

So this function attempts to read the base DPCD caps for aux. That’s the main-character move. 👑

On top of that, it also checks for and reads the extended DPRX caps — specifically DP_DP13_DPCD_REV — if they’re present. Not me checking if the extended caps are available and then reading them, because that is literally what it does. 😭💜

⭐ RETURN ⭐

  • 0 if the DPCD was read successfully 🎉
  • negative error code otherwise 💀

🌈 SEE ALSO 🌈

fr fr, that’s the whole page: read the caps, check the extended caps if they’re there, return 0 or a negative error code, and then go hang out with the entire DP helper friend group. iykyk 💖

Catch you later, bestie — this page’s source/version is ./drivers/gpu/drm/display, dated October 2026, and it’s all about drm_dp_read_dpcd_caps(9) 🎀✨🦋

📦 where this page comes from