cxl_region_...width_update(9)

💅 cxl_region_...width_update(9) — like, the abbreviated header bestie, because the real one is cxl_region_shared_upstream_bandwidth_update and it would NOT fit 🎀

okay so this is a page straight out of the Kernel API Manual, and before you ask — yes, the header up top literally abbreviates the function name with ... because it's that long. iconic, honestly. anyway. let's get into it ✨

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🌸 NAME 🌸

cxl_region_shared_upstream_bandwidth_update — recalculates the bandwidth for the region 🫶

✨ SYNOPSIS ✨

void cxl_region_shared_upstream_bandwidth_update (struct cxl_region
*cxlr );

🎀 ARGUMENTS 🎀

• cxlr — the cxl region you want to recalculate, bestie. that's the whole vibe.

🦋 DESCRIPTION 🦋

so the way this works is it walks the topology from bottom up and calculates the bandwidth. no cap, bottom to top, that's the direction. 🧚

here's the lil journey it goes on, in order:

1. it starts at the endpoints
2. then it processes at the switches, if any (if any!! conditional!! 👀)
3. then at the rootport level
4. then at the host bridge level
5. and finally aggregates at the region 💖

literally just a whole climb up the stack ending in one big aggregate moment. main character energy fr fr.

🔥 SEE ALSO 🔥

• the kernel file ./drivers/cxl/core/cdat.c
• cxl_coordinates_combine(9)
• cxl_endpoint_gather_bandwidth(9)
• cxl_switch_gather_bandwidth(9)
• cxl_rp_gather_bandwidth(9)
• cxl_hb_gather_bandwidth(9)
• cxl_region_update_bandwidth(9)

like, go read those too, they're all in the group chat 💅

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ngl the footer is giving very much "signed, sealed, delivered" — this one lives at ./drivers/cxl/core, and it's dated October 2026 🍓 mwah, that's the whole page, mwah 💜