radeon_atom_pick_pll(9)

🌸 NAME 🌸

radeon_atom_pick_pll — Allocate a PPLL for use by the crtc. okay bestie, yes, this is the radeon_atom_pick_pll(9) page from the Kernel API Manual, and it's giving "tiny function, very specific PLL allocation era" 💅✨

✨ SYNOPSIS ✨

int radeon_atom_pick_pll (struct drm_crtc *crtc );

🎀 ARGUMENTS 🎀

• crtc — drm crtc. That's it, that's the argument, no cap. 🫶

💅 DESCRIPTION 💅

okay so this function returns the PPLL (Pixel PLL) that the crtc should use. For DP monitors, a single PPLL can be used for all DP crtcs/encoders — shared queen behavior, lowkey iconic. For non-DP monitors, a dedicated PPLL must be used. periodt.

If a particular board has an external DP PLL, return ATOM_PPLL_INVALID to skip PLL programming, because there is no need to program the PLL itself. And if we are not able to allocate a PLL, return ATOM_PPLL_INVALID to skip PLL programming to avoid messing up an existing monitor. fr fr, do not mess up the existing monitor.

🚨 ATOM_PPLL_INVALID is the "skip PLL programming" signal in both of those situations — external DP PLL on the board, or allocation failed. Keep that meaning intact, bestie.

🔥 Asic specific PLL information 🔥

💖 DCE 8.x KB/KV 💖

• PPLL1, PPLL2 are available for all UNIPHY (both DP and non-DP) CI
• PPLL0, PPLL1, PPLL2 are available for all UNIPHY (both DP and non-DP) and DAC

🌸 DCE 6.1 🌸

• PPLL2 is only available to UNIPHYA (both DP and non-DP)
• PPLL0, PPLL1 are available for UNIPHYB/C/D/E/F (both DP and non-DP)

🌈 DCE 6.0 🌈

• PPLL0 is available to all UNIPHY (DP only)
• PPLL1, PPLL2 are available for all UNIPHY (both DP and non-DP) and DAC

🦋 DCE 5.0 🦋

• DCPLL is available to all UNIPHY (DP only)
• PPLL1, PPLL2 are available for all UNIPHY (both DP and non-DP) and DAC

⭐ DCE 3.0/4.0/4.1 ⭐

• PPLL1, PPLL2 are available for all UNIPHY (both DP and non-DP) and DAC

💜 SEE ALSO 💜

• Kernel file: ./drivers/gpu/drm/radeon/atombios_crtc.c
• radeon_get_pll_use_mask(9)
• radeon_get_shared_dp_ppll(9)
• radeon_get_shared_nondp_ppll(9)

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mwah 💋 this iconic page is from ./drivers/gpu/drm/radeon, dated October 2026, and it's the radeon_atom_pick_pll(9) page — bye bestie, go pick a PPLL responsibly 🫶✨