[PATCH rtw-next v3 2/3] wifi: rtw88: usb: only let the frames a dozing station needs use the after-DTIM queue
From: Mehmet Fide <hidden>
Date: 2026-09-10 08:17:23
Also in:
lkml
Subsystem:
realtek wireless driver (rtw88), the rest · Maintainers:
Ping-Ke Shih, Linus Torvalds
From: Mehmet Fide <redacted> With the budget in place the high queue can no longer take the chip down, but ordinary chatter still competes with the frames a sleeping station actually needs. mac80211 marks every broadcast and multicast frame with IEEE80211_TX_CTL_SEND_AFTER_DTIM while a station dozes, mDNS and SSDP included, so under normal traffic the budget is spent on frames nobody waits for. Do what the vendor driver does with its default "allow special" high queue filter: admit only ARP, EAPOL and DHCP to the after-DTIM path, the frames a station coming out of power save has to see; everything else goes out on its access category queue at line rate. The frames are classified the way rtw89_core_tx_btc_spec_pkt_notify() does it, from skb->protocol and the network and transport header offsets that mac80211 keeps from the netdev path; EAPOL is the control port flag. Frames the AP relays between its own stations arrive as ETH_P_802_3 and are not inspected, they leave on the access category queue. With the filter in place the page pool stays at 1803 through the same 180 second storm, a DHCP flood still takes the after-DTIM path (and is then held by the budget), and join/ping cycling without power save is unchanged (10/10). Signed-off-by: Mehmet Fide <redacted> --- v3: - the IP/UDP test written in positive form (Ping-Ke) drivers/net/wireless/realtek/rtw88/usb.c | 27 ++++++++++++++++++++++-- 1 file changed, 25 insertions(+), 2 deletions(-)
diff --git a/drivers/net/wireless/realtek/rtw88/usb.c b/drivers/net/wireless/realtek/rtw88/usb.c
index a03896260f1a..715a2ce342d9 100644
--- a/drivers/net/wireless/realtek/rtw88/usb.c
+++ b/drivers/net/wireless/realtek/rtw88/usb.c@@ -2,9 +2,11 @@ /* Copyright(c) 2018-2019 Realtek Corporation */ +#include <linux/ip.h> #include <linux/module.h> -#include <linux/usb.h> #include <linux/mutex.h> +#include <linux/udp.h> +#include <linux/usb.h> #include "main.h" #include "debug.h" #include "mac.h"
@@ -562,6 +564,27 @@ static int rtw_usb_write_data_h2c(struct rtw_dev *rtwdev, u8 *buf, u32 size) return rtw_usb_write_data(rtwdev, &pkt_info, buf); } +static bool rtw_usb_bmc_needs_dtim(struct sk_buff *skb) +{ + struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); + struct udphdr *udphdr; + + if (info->control.flags & IEEE80211_TX_CTRL_PORT_CTRL_PROTO) + return true; + + if (skb->protocol == htons(ETH_P_ARP)) + return true; + + if (skb->protocol == htons(ETH_P_IP) && + ip_hdr(skb)->protocol == IPPROTO_UDP) { + udphdr = udp_hdr(skb); + + return udphdr->dest == htons(67) || udphdr->dest == htons(68); + } + + return false; +} + #define RTW_USB_HIQ_REFILL_INTERVAL (HZ / 10) /* one unit of budget per 100 ms */ #define RTW_USB_HIQ_BUDGET_MAX 16
@@ -604,7 +627,7 @@ static u8 rtw_usb_tx_queue_mapping_to_qsel(struct rtw_usb *rtwusb, else if (is_broadcast_ether_addr(hdr->addr1) || is_multicast_ether_addr(hdr->addr1)) qsel = (info->flags & IEEE80211_TX_CTL_SEND_AFTER_DTIM) && - rtw_usb_hiq_take_budget(rtwusb) ? + rtw_usb_bmc_needs_dtim(skb) && rtw_usb_hiq_take_budget(rtwusb) ? TX_DESC_QSEL_HIGH : skb->priority; else if (skb_get_queue_mapping(skb) <= IEEE80211_AC_BK) qsel = skb->priority;
--
2.55.0