STRUCT DMATEST_PARAMS(9)

💅 struct dmatest_params(9) — bestie edition 🎀

okay so first things first: this is a page from the Kernel API Manual, and we're talking about struct dmatest_params — the literal vibe-check control panel for the dmatest situation. sit down, grab a strawberry drink 🍓, and let's get into it.

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✨ NAME ✨

struct dmatest_params — test parameters. that's it, that's the whole vibe. it's the little struct that holds all the knobs you can twist before the test runs. iconic honestly 👑

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🌸 SYNOPSIS 🌸

here's the whole thing laid out, and no i did not touch a single character, look:

struct dmatest_params {
    bool nobounce;
    unsigned int    buf_size;
    char channel[20];
    char device[32];
    unsigned int    threads_per_chan;
    unsigned int    max_channels;
    unsigned int    iterations;
    unsigned int    xor_sources;
    unsigned int    pq_sources;
    int timeout;
    bool noverify;
    bool norandom;
    int alignment;
    unsigned int    transfer_size;
    bool polled;
 };

like… she has range 💜. bools, unsigned ints, chars in arrays, an int or two — a whole little ensemble cast. main character energy fr fr.

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🦋 Members 🦋

okay this is the part where we meet everyone in the group chat, one by one:

• nobounce — prevents using the swiotlb buffer. like… no bouncing. we stay grounded 🫶
• buf_size — the size of the memcpy test buffer. it is what it says on the tin, bestie ✨
• channel — the bus ID of the channel to test. a char array of 20, so 👀 watch your length
• device — the bus ID of the DMA Engine to test. this one gets 32 chars of room, generous queen 💅
• threads_per_chan — how many threads get started per channel. the more the merrier, allegedly
• max_channels — the maximum number of channels to use. a whole ceiling on the chaos
• iterations — how many iterations happen before stopping the test. iykyk 😭
• xor_sources — the number of xor source buffers
• pq_sources — the number of p+q source buffers. p and q, both invited to the party 🎀
• timeout — transfer timeout in msec, and lowkey important: -1 means infinite timeout. no clock, no stress ⭐
• noverify — disables data verification. turning off the checking era 🙈
• norandom — disables random offset setup. we're going predictable this time
• alignment — custom data address alignment, taken as 2^alignment. yes it's an exponent, no you can't just pass the byte count, read it again bestie 💀
• transfer_size — custom transfer size in bytes
• polled — use polling for completion instead of interrupts. different technique, same goal 🌈

no cap: every single field is listed above. if you were looking for a shortcut through this list — there isn't one, and honestly why would you want one 💖

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🔥 SEE ALSO 🔥

• Kernel file ./drivers/dma/dmatest.c
• struct dmatest_info(9)

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and that's the whole page, periodt 👑. this lil beauty lives in ./drivers/dma, dated October 2026 — so yes, mark your calendars, the struct dmatest_params(9) girlies are thriving 🧚💜 go read dmatest.c and slay ✨