QUEUE CONTROL UNIT (QCU) DCF CONTROL UNIT (DCU) FUNCTIONS(9)

💖 Queue Control Unit (QCU)/DCF Control Unit (DCU) functions 💖

okay bestie, quick vibe check: this page lives in the Kernel API Manual, and it’s all about how the QCU/DCU girlies handle TX queues. ✨

Here we setup parameters for the 12 available TX queues. Note that on the various registers we can usually only map the first 10 of them so basically we have 10 queues to play with. Each queue has a matching QCU that controls when the queue will get triggered and multiple QCUs can be mapped to a single DCU that controls the various DFS parameters for the various queues. In our setup we have a 1:1 mapping between QCUs and DCUs allowing us to have different DFS settings for each queue. periodt. 💅

When a frame goes into a TX queue, QCU decides when it’ll trigger a transmission based on various criteria (such as how many data we have inside it's buffer or -if it's a beacon queue- if it's time to fire up the queue based on TSF etc), DCU adds backoff, IFSes etc and then a scheduler (arbitrator) decides the priority of each QCU based on it's configuration (e.g. beacons are always transmitted when they leave DCU bypassing all other frames from other queues waiting to be transmitted). After a frame leaves the DCU it goes to PCU for further processing and then to PHY for the actual transmission. it’s giving whole hardware pipeline main character energy, fr fr. 🔥

✨ SEE ALSO ✨

• Kernel file ./drivers/net/wireless/ath/ath5k/qcu.c
• ath5k_hw_num_tx_pending(9)
• ath5k_hw_release_tx_queue(9)
• ath5k_cw_validate(9)
• ath5k_hw_get_tx_queueprops(9)
• ath5k_hw_set_tx_queueprops(9)
• ath5k_hw_setup_tx_queue(9)
• ath5k_hw_set_tx_retry_limits(9)
• ath5k_hw_reset_tx_queue(9)
• ath5k_hw_set_ifs_intervals(9)
• ath5k_hw_init_queues(9)

Later, bestie 💖 — this one signs off from ./drivers/net/wireless/ath/ath5k, October 2026, for Queue Contr...U) functions(9). 🎀