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RTL8814AU: match TX descriptor to kernel-driver field-for-field #28

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RTL8814AU: match TX descriptor to kernel-driver field-for-field #28

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53 changes: 27 additions & 26 deletions src/RtlJaguarDevice.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -137,12 +137,8 @@ bool RtlJaguarDevice::send_packet(const uint8_t *packet, size_t length) {

SET_TX_DESC_DATA_BW_8812(usb_frame, BWSettingOfDesc);

/* Upstream rtl8814a_xmit.c sets ONLY LAST_SEG=1 (not FIRST_SEG) for a
* single-fragment frame, and MACID = bmc_camid which is 0 for the
* broadcast/default CAM entry. Our previous values (FIRST_SEG=1, MACID=1)
* caused the chip to silently reject every bulk-OUT — verified by
* usbmon trace comparing the OOT-driver's working TX descriptor to
* ours at byte offsets 3 (flags) and 4 (MACID). */
/* Single-fragment frame: LAST_SEG=1 (no FIRST_SEG); OWN=1 so chip
* processes the descriptor. */
SET_TX_DESC_LAST_SEG_8812(usb_frame, 1);
SET_TX_DESC_OWN_8812(usb_frame, 1);

Expand All @@ -152,40 +148,45 @@ bool RtlJaguarDevice::send_packet(const uint8_t *packet, size_t length) {
SET_TX_DESC_OFFSET_8812(usb_frame,
static_cast<uint8_t>(TXDESC_SIZE + OFFSET_SZ));

SET_TX_DESC_MACID_8812(usb_frame, static_cast<uint8_t>(0x00));
/* Match the kernel-driver TX descriptor field-for-field. usbmon
* capture of kernel-driver TX in monitor mode (8814AU, channel 6)
* shows these exact values; previous comments in this file proposed
* different values based on speculative reasoning that didn't hold
* up under empirical comparison:
*
* MACID = 1 (broadcast/default CAM, not 0)
* RATE_ID = 8 (non-VHT) (kernel uses 8, not 7)
* GID = 63 (= 0x3F) (no-group default; previously left 0)
* SW_DEFINE = 1 (DriverFixedRate flag; previously 0)
* RETRY_LIMIT_ENABLE = 1, DATA_RETRY_LIMIT = 12
* (mgmt-frame defaults from upstream
* rtl8814au_xmit.c:267; previously
* both 0)
* SPE_RPT = 0 (kernel does NOT set this; previously 1)
* DISABLE_FB = 0 (kernel does NOT set this; previously 1)
* HWSEQ_EN = 1 (chip auto-fills 802.11 SEQ; unchanged)
*/
SET_TX_DESC_MACID_8812(usb_frame, static_cast<uint8_t>(0x01));

if (!vht) {
rate_id = 7;
rate_id = 8;
} else {
rate_id = 9;
}

SET_TX_DESC_BMC_8812(usb_frame, 1);
SET_TX_DESC_RATE_ID_8812(
usb_frame,
static_cast<uint8_t>(rate_id));
SET_TX_DESC_RATE_ID_8812(usb_frame, static_cast<uint8_t>(rate_id));

SET_TX_DESC_QUEUE_SEL_8812(usb_frame, 0x12);
/* Upstream 8814 uses HWSEQ_EN=1 (chip auto-fills the 802.11 SEQ number)
* with the descriptor SEQ field zero. Verified by usbmon trace: OOT
* driver sets bit 15 of word 8 (byte 33 = 0x80). Our previous path set
* HWSEQ_EN=0 + SEQ field manually — the chip's HWSEQ-disabled path may
* require additional driver-side sequence handling we don't have. */
SET_TX_DESC_HWSEQ_EN_8812(usb_frame, static_cast<uint8_t>(1));
/* OOT-driver descriptor has SPE_RPT=1 (bit 19 of word 2 = byte 10 bit 3).
* Special TX report — chip may use this to signal TX-complete back to the
* driver. Without it, the TX queue may stall waiting for a status ack we
* never enable. */
SET_TX_DESC_SPE_RPT_8812(usb_frame, static_cast<uint8_t>(1));
/* OOT-driver descriptor has RETRY_LIMIT_ENABLE=0 (let chip use its
* default retry policy). Setting RETRY_LIMIT_ENABLE=1 with
* DATA_RETRY_LIMIT=0 means "give up after 0 retries" — the chip drops
* the frame and never even attempts to TX. */
SET_TX_DESC_GID_8812(usb_frame, static_cast<uint8_t>(0x3F));
SET_TX_DESC_SW_DEFINE_8812(usb_frame, static_cast<uint16_t>(0x001));
SET_TX_DESC_RETRY_LIMIT_ENABLE_8812(usb_frame, 1);
SET_TX_DESC_DATA_RETRY_LIMIT_8812(usb_frame, 12);
if (sgi) {
_logger->info("short gi enabled,set sgi");
SET_TX_DESC_DATA_SHORT_8812(usb_frame, 1);
}
SET_TX_DESC_DISABLE_FB_8812(usb_frame, 1);
SET_TX_DESC_USE_RATE_8812(usb_frame, 1);
SET_TX_DESC_TX_RATE_8812(usb_frame,
static_cast<uint8_t>(MRateToHwRate(
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