rt2x00usb_v...request_buff(9)

💅 rt2x00usb_vendor_request_buff — Kernel API Manual ✨

okay so bestie, you're looking at the <cyan>rt2x00usb_vendor_request_buff(9)</cyan> page from the Kernel API Manual. it's giving "kernel driver internals" and honestly? kind of iconic. let's get into it 🫶

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🌸 NAME 🌸

rt2x00usb_vendor_request_buff — send a register command to the device, but make it buffered ✨

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🎀 SYNOPSIS 🎀

int rt2x00usb_vendor_request_buff (struct rt2x00_dev *rt2x00dev , const
       u8 request , const u8 requesttype , const u16 offset , void *buffer ,
       const u16 buffer_length );

that's the whole signature, no cap. six things go in, one int comes out 💫

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🦋 ARGUMENTS 🦋

• rt2x00dev — pointer to struct rt2x00_dev. that's your device bestie, the main character here 👑
• request — the USB vendor command. (peep enum rt2x00usb_vendor_request for the whole menu, iykyk)
• requesttype — the request type, laid out as USB_VENDOR_REQUEST_*
• offset — the register offset you're doing the action on 📍
• buffer — the buffer where the device will read from / write to all the info 💾
• buffer_length — the size of that buffer, fr fr, don't get it wrong

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💖 DESCRIPTION 💖

so here's the vibe: this function uses a cache that was previously allocated with kmalloc to talk to the device. no fresh allocation drama mid-request, we're reusing ✨

the contents of the buffer pointer get copied into that cache when you're writing, or read back out of the cache when you're reading. simple as that, periodt.

⚠️ big important warning, bestie, do not skip this: buffers sent to rt2x00usb_vendor_request must be allocated with kmalloc. like, must must. that's literally the entire reason this function uses a previously-allocated cache — because that cache was allocated properly. no stack buffers, no vibes-based allocation, okay? 😭💀

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⭐ SEE ALSO ⭐

kernel file ./drivers/net/wireless/ralink/rt2x00/rt2x00usb.h, plus the whole friend group:

• enum rt2x00usb_vendor_request(9)
• enum rt2x00usb_mode_offset(9)
• rt2x00usb_vendor_request(9)
• rt2x00usb_vendor_request_sw(9)
• rt2x00usb_eeprom_read(9)
• rt2x00usb_register_read(9)
• rt2x00usb_register_read_lock(9)
• rt2x00usb_register_multiread(9)
• rt2x00usb_register_write(9)
• rt2x00usb_register_write_lock(9)
• rt2x00usb_register_multiwrite(9)
• rt2x00usb_regbusy_read(9)
• rt2x00usb_register_read_async(9)
• struct queue_entry_priv_usb(9)
• struct queue_entry_priv_usb_bcn(9)
• rt2x00usb_kick_queue(9)
• rt2x00usb_flush_queue(9)
• rt2x00usb_watchdog(9)

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and that's the page!! 🧚 mwah 💋

shoutout to ./drivers/net/wireless/ralink/... for the source, the October 2026 date, and the rt2x00usb_v...request_buff(9) footer situation — we love a documented kernel function, obsessed actually 🍓💜