radeon_uvd_...pll_dividers(9)

🦋 radeon_uvd_...pll_dividers(9) 🦋

okay so bestie, this is a page from the Kernel API Manual and honestly? it's giving "small function, big responsibility" and i'm obsessed. sit down, grab a lil snack 🍓, and let's get into it.

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✨ NAME ✨

radeon_uvd_calc_upll_dividers — calc UPLL clock dividers 💅

like, it calculates the clock dividers for the UPLL. that's the whole vibe. no cap.

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🌸 SYNOPSIS 🌸

int radeon_uvd_calc_upll_dividers (struct radeon_device *rdev , unsigned
vclk , unsigned dclk , unsigned vco_min , unsigned vco_max , unsigned
fb_factor , unsigned fb_mask , unsigned pd_min , unsigned pd_max ,
unsigned pd_even , unsigned *optimal_fb_div , unsigned *optimal_vclk_div
, unsigned *optimal_dclk_div );

it returns an int, it takes a whole squad of unsigned args, and yes there are three pointers at the end doing the actual delivering of results. main character energy fr fr 👑

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🎀 ARGUMENTS 🎀

• rdev — a radeon_device pointer. literally just your radeon device, hi bestie 🫶
• vclk — the VCLK you want. your wish, your dream ✨
• dclk — the DCLK you want. matching set, cute 🎀
• vco_min — minimum VCO frequency. the floor, don't go below it 💀
• vco_max — maximum VCO frequency. the ceiling, don't go above it 🚫
• fb_factor — factor to multiply vco freq with. math time, slay 🧮
• fb_mask — limit and bitmask for feedback divider. mask on, mask off 🎭
• pd_min — post divider minimum. tiny king 👑
• pd_max — post divider maximum. big king 👑
• pd_even — post divider must be even above this value. even numbers only past this point, them's the rules 🚨
• optimal_fb_div — the resulting feedback divider gets written here 💖
• optimal_vclk_div — the resulting vclk post divider lands here 💖
• optimal_dclk_div — the resulting dclk post divider goes here too 💖

yes bestie, those last three are output params — the function hands you back the goods through the pointers 🔥

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🌈 DESCRIPTION 🌈

okay so the actual job: it calculates dividers for UVD's UPLL. specifically R6xx-SI, except APUs — like, that tag matters, don't @ me. iykyk 🦋

and the returns? immaculate. it returns zero on success, and on error it returns -EINVAL. that's it. that's the contract. periodt 💅

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⭐ SEE ALSO ⭐

• Kernel file ./drivers/gpu/drm/radeon/radeon_uvd.c — go read the source, it's right there 🧚
• radeon_uvd_count_handles(9) — sibling function, say hi for me 👋

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and that's the whole page, bestie 💜 this lil gem lives over in ./drivers/gpu/drm/radeon and the docs are dated October 2026 — write it in your calendar, screenshot it, frame it, whatever you gotta do. mwah 😭💖