panthor_fw_toggle_reqs(9)

💅 panthor_fw_toggle_reqs(9) — like, the Kernel API Manual page, bestie 🎀

okay so bestie, pull up a chair, we're reading a kernel API manual page today (that's the manual name, Kernel API Manual, slay) and honestly this one is a whole little vibe. it's all about poking bits so the firmware notices you. let's go ✨

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🌸 NAME 🌸

panthor_fw_toggle_reqs — toggles acknowledge bits to send an event to the FW. that's it, that's the whole job. iconic behaviour, tbh 💅

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✨ SYNOPSIS ✨

panthor_fw_toggle_reqs (__iface , __in_reg , __out_reg , __mask );

she takes four things and she takes them very seriously. no cap.

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🫶 ARGUMENTS 🫶

• __iface — the interface you're operating on. the one we're doing bits in 💖
• __in_reg — name of the register to update in the input section of the interface.
• __out_reg — name of the register to take as a reference in the output section of the interface. yes, she's the reference, she's the moment.
• __mask — the mask to apply to the update. be normal about it.

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💀 DESCRIPTION 💀

okay so here's the lore 🔥 the Host -> FW event/message passing was designed to be lockless, with each side of the channel having its own writable section. no fighting over the same pen, love that for them 🦋

events get signaled as a difference between the host side and the FW side in the req/ack registers. when a bit differs → there's an event pending 👀. when they're the same → nothing needs attention, carry on, nothing to see here 💤

this helper lets you update the req register based on the current value of the ack register managed by the FW. toggling a specific bit will flag an event ⭐

⚠️ important bestie: in order for events to be re-evaluated, the interface doorbell needs to be rung. like, you gotta ring it. no ringing, no re-evaluation. that's the rule 🎀

Concurrent accesses to the same req register is covered. ✅ (she's handled, we're fine, don't spiral)

Anything requiring atomic updates to multiple registers requires a dedicated lock. 🔒 so if you're doing multi-register atomic stuff, get yourself a lock, don't be out here raw-dogging it, i'm begging 🙈

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👑 SEE ALSO 👑

• kernel file ./drivers/gpu/drm/panthor/panthor_fw.h
• struct panthor_fw_cs_iface(9)
• struct panthor_fw_csg_iface(9)
• struct panthor_fw_global_iface(9)
• panthor_fw_update_reqs(9)

they're all in the group chat, go say hi 🌈

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k bye bestie, this page came to you straight from ./drivers/gpu/drm/panthor, dated October 2026, version vibes immaculate, panthor_fw_toggle_reqs(9) 4ever 💜🫶🌸