From 8c21388603ce57c09782cb0663f0648b6a872c34 Mon Sep 17 00:00:00 2001 From: Bryan Biedenkapp Date: Thu, 5 Mar 2026 13:52:30 -0500 Subject: [PATCH] cherrypick changes for V.24 fixes from tsawyer:dvmhost:codex/fix-v24-r05a05-prready; --- src/host/Host.P25.cpp | 13 +++++- src/host/modem/Modem.cpp | 22 ++++++++-- src/host/modem/ModemV24.cpp | 80 ++++++++++++++++++++++++++----------- 3 files changed, 85 insertions(+), 30 deletions(-) diff --git a/src/host/Host.P25.cpp b/src/host/Host.P25.cpp index 1db6a6ba..6fc74793 100644 --- a/src/host/Host.P25.cpp +++ b/src/host/Host.P25.cpp @@ -4,7 +4,8 @@ * GPLv2 Open Source. Use is subject to license terms. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * -* Copyright (C) 2017-2024 Bryan Biedenkapp, N2PLL +* Copyright (C) 2017-2026 Bryan Biedenkapp, N2PLL +* Copyright (C) 2026 Timothy Sawyer, WD6AWP * */ #include "Defines.h" @@ -255,6 +256,14 @@ void* Host::threadP25Writer(void* arg) if (nextLen > 0U) { bool ret = host->m_modem->hasP25Space(nextLen); + + // are we connected to a V.24 device? if so, always force + // allow the write, V.24 modem status space can lag at call start; do not block + // initial Net->RF voice frames on stale p25Space accounting + if (host->m_modem->isV24Connected()) { + ret = true; + } + if (ret) { bool imm = false; uint32_t len = host->m_p25->getFrame(data, &imm); @@ -267,7 +276,7 @@ void* Host::threadP25Writer(void* arg) // if the state is P25; write P25 frame data if (host->m_state == STATE_P25) { - host->m_modem->writeP25Frame(data, len); + host->m_modem->writeP25Frame(data, len, imm); afterWriteCallback(); diff --git a/src/host/modem/Modem.cpp b/src/host/modem/Modem.cpp index 18a95e3f..250c1db2 100644 --- a/src/host/modem/Modem.cpp +++ b/src/host/modem/Modem.cpp @@ -5,8 +5,9 @@ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * Copyright (C) 2011-2021 Jonathan Naylor, G4KLX - * Copyright (C) 2017-2024 Bryan Biedenkapp, N2PLL + * Copyright (C) 2017-2026 Bryan Biedenkapp, N2PLL * Copyright (C) 2021 Nat Moore + * Copyright (C) 2026 Timothy Sawyer, WD6AWP * */ #include "Defines.h" @@ -125,7 +126,7 @@ Modem::Modem(port::IModemPort* port, bool duplex, bool rxInvert, bool txInvert, m_nxdnFifoLength(NXDN_TX_BUFFER_LEN), m_adcOverFlowCount(0U), m_dacOverFlowCount(0U), - m_v24Connected(true), + m_v24Connected(false), m_modemState(STATE_IDLE), m_buffer(nullptr), m_length(0U), @@ -754,7 +755,7 @@ void Modem::clock(uint32_t ms) // flag indicating if free space is being reported in 16-byte blocks instead of LDUs bool spaceInBlocks = (m_buffer[3U] & 0x80U) == 0x80U; - m_v24Connected = true; + m_v24Connected = false; m_modemState = (DVM_STATE)m_buffer[4U]; m_tx = (m_buffer[5U] & 0x01U) == 0x01U; @@ -1517,7 +1518,9 @@ bool Modem::writeP25Frame(const uint8_t* data, uint32_t length, bool imm) uint32_t len = length + 2U; // write or buffer P25 data to air interface - if (m_p25Space >= length) { + // for V.24/DFSI, the modem status space value may lag call startup; do + // not block initial Net->RF frames solely on stale p25Space + if (m_p25Space >= length || isV24Connected()) { if (m_debug) LogDebugEx(LOG_MODEM, "Modem::writeP25Frame()", "immediate write (len %u)", length); if (m_trace) @@ -1529,6 +1532,17 @@ bool Modem::writeP25Frame(const uint8_t* data, uint32_t length, bool imm) return false; } + /* + ** bryanb: this change is from Tim's fork, but it is a bit concerning, because we're not adjusting + ** available modem space appropriately, if there isn't enough space for the frame being written in the first + ** place -- for now i've commented this out but included it, reasonably speaking m_p25Space doesn't even + ** matter because writeSerial() in ModemV24 doesn't even check this before writing to the port + */ +/* + if (m_p25Space >= length) { + m_p25Space -= length; + } +*/ m_p25Space -= length; } else { diff --git a/src/host/modem/ModemV24.cpp b/src/host/modem/ModemV24.cpp index eb2b9e2a..b9f39f06 100644 --- a/src/host/modem/ModemV24.cpp +++ b/src/host/modem/ModemV24.cpp @@ -4,8 +4,9 @@ * GPLv2 Open Source. Use is subject to license terms. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * - * Copyright (C) 2024-2025 Bryan Biedenkapp, N2PLL + * Copyright (C) 2024-2026 Bryan Biedenkapp, N2PLL * Copyright (C) 2024 Patrick McDonnell, W3AXL + * Copyright (C) 2026 Timothy Sawyer, WD6AWP * */ #include "Defines.h" @@ -394,6 +395,14 @@ void ModemV24::clock(uint32_t ms) int len = 0; // write anything waiting to the serial port + + /* + ** bryanb: Tim's fork changes the order of this, however, this is a terrible idea becuase it will ultimately break + ** the intended purpose of this code which is to allow prioritized frames, reasonably speaking this code should + ** not cause problems for timing -- but we should keep an eye on this (if its problematic for some reason, + ** we can consider perhaps adding a flag that disables the immediate queue, forcing all packets in to the normal + ** queue) + */ if (!m_txImmP25Queue.isEmpty()) len = writeSerial(&m_txImmP25Queue); else @@ -477,6 +486,8 @@ int ModemV24::writeSerial(RingBuffer* queue) * | Length | Tag | int64_t timestamp in ms | data | */ + std::lock_guard lock(m_txP25QueueLock); + // check empty if (queue->isEmpty()) return 0U; @@ -486,24 +497,19 @@ int ModemV24::writeSerial(RingBuffer* queue) ::memset(length, 0x00U, 2U); queue->peek(length, 2U); - // convert length byets to int + // convert length bytes to int uint16_t len = 0U; len = (length[0U] << 8) + length[1U]; - // this ensures we never get in a situation where we have length & type bytes stuck in the queue by themselves + // this ensures we never get in a situation where we have length bytes stuck in the queue by themselves if (queue->dataSize() == 2U && len > queue->dataSize()) { queue->get(length, 2U); // ensure we pop bytes off return 0U; } - // check available modem space - if (m_p25Space < len) - return 0U; - - std::lock_guard lock(m_txP25QueueLock); - // get current timestamp int64_t now = std::chrono::duration_cast(std::chrono::system_clock::now().time_since_epoch()).count(); + int64_t ts = 0L; // peek the timestamp to see if we should wait if (queue->dataSize() >= 11U) { @@ -512,7 +518,6 @@ int ModemV24::writeSerial(RingBuffer* queue) queue->peek(lengthTagTs, 11U); // get the timestamp - int64_t ts; assert(sizeof ts == 8); ::memcpy(&ts, lengthTagTs + 3U, 8U); @@ -524,23 +529,34 @@ int ModemV24::writeSerial(RingBuffer* queue) // check if we have enough data to get everything - len + 2U (length bytes) + 1U (tag) + 8U (timestamp) if (queue->dataSize() >= len + 11U) { - // Get the length, tag and timestamp - uint8_t lengthTagTs[11U]; - queue->get(lengthTagTs, 11U); - - // Get the actual data - DECLARE_UINT8_ARRAY(buffer, len); - queue->get(buffer, len); - - // Sanity check on data tag + // peek the full entry so we can keep it queued if a write fails + DECLARE_UINT8_ARRAY(entry, len + 11U); + queue->peek(entry, len + 11U); + + // get the length, tag, timestamp and payload pointers from peeked data + uint8_t* lengthTagTs = entry; + uint8_t* buffer = entry + 11U; + + // sanity check on data tag uint8_t tag = lengthTagTs[2U]; if (tag != TAG_DATA) { LogError(LOG_MODEM, "Got unexpected data tag from TX P25 ringbuffer! %02X", tag); + + // drop malformed entry so we can recover queue alignment + DECLARE_UINT8_ARRAY(discard, len + 11U); + queue->get(discard, len + 11U); return 0U; } - // we already checked the timestamp above, so we just get the data and write it - return m_port->write(buffer, len); + // we already checked the timestamp above, so we just write it + int ret = m_port->write(buffer, len); + if (ret > 0) { + // only remove an entry once it was written successfully + DECLARE_UINT8_ARRAY(discard, len + 11U); + queue->get(discard, len + 11U); + } + + return ret; } return 0U; @@ -2363,12 +2379,19 @@ bool ModemV24::queueP25Frame(uint8_t* data, uint16_t len, SERIAL_TX_TYPE msgType std::lock_guard lock(m_txP25QueueLock); // check available ringbuffer space + // keep one byte of headroom to avoid the ring buffer "full == empty" + // ambiguity (iPtr == oPtr) when a write would consume exactly all free space + uint32_t needed = len + 11U; if (imm) { - if (m_txImmP25Queue.freeSpace() < (len + 11U)) + uint32_t free = m_txImmP25Queue.freeSpace(); + if (free <= needed) { return false; + } } else { - if (m_txP25Queue.freeSpace() < (len + 11U)) + uint32_t free = m_txP25Queue.freeSpace(); + if (free <= needed) { return false; + } } // convert 16-bit length to 2 bytes @@ -2429,6 +2452,10 @@ void ModemV24::startOfStreamV24(const p25::lc::LC& control) { m_txCallInProgress = true; + // start each Net->RF stream with a fresh scheduler epoch so a new call + // doesn't inherit a future-biased timestamp from the previous call + m_lastP25Tx = 0U; + MotStartOfStream start = MotStartOfStream(); start.setOpcode(m_rtrt ? MotStartStreamOpcode::TRANSMIT : MotStartStreamOpcode::RECEIVE); start.setParam1(DSFI_MOT_ICW_PARM_PAYLOAD); @@ -2546,6 +2573,10 @@ void ModemV24::startOfStreamTIA(const p25::lc::LC& control) m_txCallInProgress = true; m_superFrameCnt = 1U; + // start each Net->RF stream with a fresh scheduler epoch so a new call + // doesn't inherit a future-biased timestamp from the previous call + m_lastP25Tx = 0U; + p25::lc::LC lc = p25::lc::LC(control); uint16_t length = 0U; @@ -2806,7 +2837,8 @@ void ModemV24::convertFromAirV24(uint8_t* data, uint32_t length, bool imm) break; case DUID::TDU: - endOfStreamV24(); // this may incorrectly sent STOP ICW's with the VOICE payload, but it's better than nothing for now + if (m_txCallInProgress) + endOfStreamV24(); break; case DUID::TDULC: