dma_async_is_tx_complete(9)

💫 dma_async_is_tx_complete — poll for transaction completion 💫

okay so this is from the Kernel API Manual and bestie, it's literally about asking "hey… is my DMA transaction done yet?" 🎀

---

🌸 NAME 🌸

dma_async_is_tx_complete — poll for transaction completion 👀

---

✨ SYNOPSIS ✨

enum dma_status dma_async_is_tx_complete (struct dma_chan *chan ,
dma_cookie_t cookie , dma_cookie_t *last , dma_cookie_t *used );

---

🦋 ARGUMENTS 🦋

• chan — the DMA channel, like the main character of this whole operation 💅
• cookie — the transaction identifier you wanna check the status of 🍪 (yes it's really called a cookie, no cap)
• last — returns the last completed cookie; can be NULL if you're not about that info rn
• used — returns the last issued cookie; can be NULL too, no pressure 🫶

---

💜 DESCRIPTION 💜

so here's the tea: if you pass in last and used, then upon return they reflect the driver's internal state ✨ and you can use them with dma_async_is_complete to check the status of multiple cookies without re-checking hardware state — which is lowkey iconic because hardware checks are expensive and nobody has time for that 🙈🔥

---

🌈 SEE ALSO 🌈

Kernel file ./include/linux/dmaengine.h and their whole friend group:

• dma_cookie_t(9)
• enum dma_status(9)
• enum dma_transaction_type(9)
• enum dma_transfer_direction(9)
• struct data_chunk(9)
• struct dma_interleaved_template(9)
• struct dma_vec(9)
• enum dma_ctrl_flags(9)
• enum sum_check_bits(9)
• enum sum_check_flags(9)
• enum dma_desc_metadata_mode(9)
• struct dma_chan_percpu(9)
• struct dma_router(9)
• struct dma_chan(9)
• struct dma_chan_dev(9)
• enum dma_slave_buswidth(9)
• struct dma_slave_config(9)
• enum dma_residue_granularity(9)
• struct dma_slave_caps(9)
• dma_filter_fn(9)
• struct dma_async_tx_descriptor(9)
• struct dma_tx_state(9)
• enum dmaengine_alignment(9)
• struct dma_slave_map(9)
• struct dma_filter(9)
• struct dma_device(9)
• dmaengine_prep_peripheral_dma_vec(9)
• dmaengine_prep_config_sg_safe(9)
• dmaengine_prep_config_single_safe(9)
• dmaengine_prep_dma_memset(9)
• dmaengine_terminate_all(9)
• dmaengine_terminate_async(9)
• dmaengine_synchronize(9)
• dmaengine_terminate_sync(9)
• dma_async_issue_pending(9)
• dma_async_is_complete(9)

---

that's the whole page bestie, go poll some transactions and slay 💖

source: ./include/linux · dated October 2026 · mwah, byeee 🧚💅