spi_mem_set_dqs(9)

📦 version 7.3.1, in nixpkgs unstable

💅 spi_mem_set_dqs — the kernel API manual, bestie edition ✨

okay so you're looking at spi_mem_set_dqs(9) and honestly? it's giving "tiny function, huge lore." let's get into it 🫶

✨ NAME ✨

spi_mem_set_dqs — marks DQS as being available 💫 (that's the whole vibe, no cap)

🌸 SYNOPSIS 🌸

void spi_mem_set_dqs (struct spi_mem *mem );

like, that's it. one arg. one dream. 🎀

🦋 ARGUMENTS 🦋

  • mem — the SPI memory. that's your girl, that's the main character here 👑

🔥 DESCRIPTION 🔥

okay bestie, story time. when you're reading at high frequencies — we're talking > 100MHz here 🏃‍♀️💨 — and especially when DTR is enabled, your transfer speed gets limited, and the reason is clock skews. literally the worst.

so here's the situation: the controller straight up does not know the board propagation delay, and it also does not know the memory chip's internal delay (that's clock in to data out, iykyk). and because it doesn't know either of those things, it can't optimize its sampling points. 😭 tragic, honestly.

but!! mitigating this limitation is possible — the glow-up is real — with the addition of a data strobe signal, commonly named DQS. ✨ iconic.

so what does this function actually do? it sets the DQS boolean if the feature is available and configured at the chip level. and yeah — controllers may query this value 👀. that's the whole thing. it ate, no crumbs. 💅

ngl this one's short but it matters — the boolean only gets set when DQS is actually available and configured at the chip level, so don't go assuming it's always on 🙈

🧚 SEE ALSO 🧚

and that's the whole page, bestie!! 🎀✨

this lil baddie lives in ./drivers/spi, dated October 2026, and the manual itself is spi_mem_set_dqs(9) — go forth and query your booleans responsibly 💖🦋🌸

📦 where this page comes from