amdgpu_pll_compute(9)

✨ NAME ✨

amdgpu_pll_compute — compute PLL paramaters 🎀 (yes bestie that's literally how the page spells it, we're keeping it, no cap)

🌸 SYNOPSIS 🌸

void amdgpu_pll_compute (struct amdgpu_device *adev , struct amdgpu_pll
*pll , u32 freq , u32 *dot_clock_p , u32 *fb_div_p , u32 *frac_fb_div_p
, u32 *ref_div_p , u32 *post_div_p );

💖 ARGUMENTS 💖

• adev — the amdgpu_device pointer, aka where all the GPU stuff lives 🫶
• pll — the amdgpu_pll struct, i.e. the info about the PLL itself
• freq — the frequency you're asking for, the whole reason we're here ✨
• dot_clock_p — out-param: the resulting pixel clock lands here
• fb_div_p — out-param: the resulting feedback divider goes here
• frac_fb_div_p — out-param: the fractional part of the feedback divider, so the vibes are precise 💅
• ref_div_p — out-param: the resulting reference divider
• post_div_p — out-param: the resulting reference divider — fr fr that's what the page says, we're just reporting it 🙈

🦋 DESCRIPTION 🦋

So the whole point: it tries to calculate the PLL parameters that'll generate the frequency you handed it. The way that math works out:

dot_clock = (ref_freq * feedback_div) / (ref_div * post_div)

That's the whole vibe check — feed it a freq, get dividers back. It's giving "calculator but make it GPU" 😭🔥

🔥 SEE ALSO 🔥

• Kernel file: ./drivers/gpu/drm/amd/amdgpu/amdgpu_pll.c
• amdgpu_pll_reduce_ratio(9)
• amdgpu_pll_get_fb_ref_div(9)
• amdgpu_pll_get_use_mask(9)
• amdgpu_pll_get_shared_dp_ppll(9)
• amdgpu_pll_get_shared_nondp_ppll(9)

These are the sibling functions, the squad, iykyk 👑

That's the page bestie — amdgpu_pll_compute(9) from the Kernel API Manual, straight out of ./drivers/gpu/drm/amd/amdgpu, dated October 2026. Go get that pixel clock, icon 💜🌸