Simone
c9b8799f69
Two things came out of preparing the suspend test, and one of them is a correction. ee1004 does not bind to this adapter. Both functionality combinations it accepts include I2C_FUNC_SMBUS_BYTE (drivers/misc/eeprom/ee1004.c:301), which this driver does not implement, so the probe fails with -EPFNOSUPPORT. The cover letter claimed BYTE_DATA and WORD_DATA "cover ee1004 and jc42" and the .rst told the reader to instantiate it; both were wrong and are corrected. jc42 is fine, it only needs BYTE_DATA and WORD_DATA, but no TSOD is populated here to bind to. The practical cost is that decode-dimms does not work through this adapter. SPD bytes stay readable byte by byte with i2cget. Receive Byte is what PawnIO implements with its pointer-select bit and what this project chose not to advertise for want of validation; that choice was not free, and adding it validated is the most useful thing left. Suspend and resume tested with continuous traffic on both adapters, s2idle and S3. Transfers recover, nothing complains. Across S3 the engine comes back reprogrammed on both channels: DATA 0x2000b600 -> 0x20005000 STATUS 0x0000500c -> 0x00005004 The command word addresses SPD 0x50 for a read and the status drops to READ_DONE alone. Linux issued none of it: the adapter was marked suspended and userspace frozen. This is consistent with firmware reading SPD during memory training on resume, and it is the first direct observation of a second master on this engine. It is also the concrete justification for restoring command state per transfer and comparing it afterwards. Add tools/test-suspend.sh, which drives that test and reports the register delta across the sleep. Traffic goes through i2c-dev rather than a bound client: with ee1004 unable to attach and no TSOD present, there is no in-kernel client to use, and the PM path exercised is the same either way -- i2c_smbus_xfer() consults __i2c_check_suspended() before reaching the adapter.
165 lines
4.7 KiB
Bash
Executable File
165 lines
4.7 KiB
Bash
Executable File
#!/usr/bin/env bash
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#
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# Suspend/resume validation with active I2C clients.
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#
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# Hammers both adapters from userspace and suspends the machine underneath the
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# traffic. The driver hands suspend and resume to the i2c core
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# (i2c_mark_adapter_suspended / _resumed), so the core must reject transfers
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# with -ESHUTDOWN for the duration and accept them again afterwards. What this
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# checks:
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#
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# Traffic goes through i2c-dev rather than a bound client driver: ee1004 needs
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# I2C_FUNC_SMBUS_BYTE, which this adapter does not implement, and no TSOD is
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# populated for jc42 to bind to. The PM path being exercised is the same one
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# either way - i2c_smbus_xfer() calls __i2c_check_suspended() before reaching
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# the adapter.
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#
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# - transfers fail while the adapter is suspended rather than touching the
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# engine or hanging;
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# - transfers succeed again after resume, with correct data;
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# - nothing in the kernel log complains.
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#
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# The machine really does suspend. Wake-up is scheduled through the RTC alarm,
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# so no key press is needed, but if the platform fails to wake you will have to
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# press the power button.
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#
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set -euo pipefail
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# shellcheck source=tools/common.sh
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source "$(dirname "$(readlink -f "$0")")/common.sh"
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MODE=freeze
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ASLEEP=20
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SPD_ADDR=0x50
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CONFIRMED=false
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READER=""
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while (($#)); do
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case $1 in
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--i-understand) CONFIRMED=true; shift ;;
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--mode) MODE=$2; shift 2 ;;
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--seconds) ASLEEP=$2; shift 2 ;;
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-h|--help)
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sed -n '3,19p' "$0"
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echo "usage: $0 --i-understand [--mode freeze|mem] [--seconds N]"
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exit 0
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;;
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*) die "unknown argument: $1" ;;
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esac
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done
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$CONFIRMED || {
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echo "This suspends the machine. Re-run with --i-understand." >&2
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exit 2
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}
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require_root
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require_cmd i2cdetect i2cget rtcwake awk
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bus_of()
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{
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i2cdetect -l | awk -v ch="$1" '
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tolower($0) ~ /imc.*channel/ && $0 ~ "channel " ch {
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sub(/^i2c-/, "", $1); print $1; exit
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}'
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}
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cleanup()
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{
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[[ -n "$READER" ]] && kill "$READER" 2>/dev/null || true
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}
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trap cleanup EXIT
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BUSES=()
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for ch in 0 1; do
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b=$(bus_of "$ch")
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[[ -n "$b" ]] || die "adapter for channel $ch not found"
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BUSES+=("$b")
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done
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echo "adapters: ${BUSES[*]}"
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for b in "${BUSES[@]}"; do
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i2cget -y "$b" "$SPD_ADDR" 0x02 >/dev/null 2>&1 ||
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die "bus $b: cannot read the SPD at $SPD_ADDR, nothing to hammer"
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echo " bus $b: SPD $SPD_ADDR responds"
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done
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BDF=$(find_pcu)
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mapfile -t REGS_BEFORE < <(snapshot_regs "$BDF")
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LOG=$(mktemp)
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DMESG_START=$(dmesg | wc -l)
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# Hammer the clients and record the outcome of every read with a timestamp.
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(
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while :; do
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for b in "${BUSES[@]}"; do
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if i2cget -y "$b" "$SPD_ADDR" 0x02 >/dev/null 2>&1; then
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printf '%s OK\n' "$(date +%s.%N)"
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else
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printf '%s FAIL\n' "$(date +%s.%N)"
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fi
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done
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sleep 0.1
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done
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) >> "$LOG" 2>&1 &
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READER=$!
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sleep 2
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BEFORE=$(date +%s)
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echo "suspending: mode=$MODE for ${ASLEEP}s"
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rtcwake -m "$MODE" -s "$ASLEEP" >/dev/null 2>&1 || die "rtcwake failed"
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AFTER=$(date +%s)
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sleep 2
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kill "$READER" 2>/dev/null || true
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READER=""
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sleep 0.5
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echo
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echo "=== result ==="
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printf 'wall clock across suspend: %ss (asked for %ss)\n' "$((AFTER - BEFORE))" "$ASLEEP"
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pre=$(awk -v t="$BEFORE" '$1 < t && $2 == "OK"' "$LOG" | wc -l)
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post=$(awk -v t="$AFTER" '$1 > t && $2 == "OK"' "$LOG" | wc -l)
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fails=$(awk '$2 == "FAIL"' "$LOG" | wc -l)
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fails_outside=$(awk -v a="$BEFORE" -v b="$AFTER" '$2 == "FAIL" && ($1 < a || $1 > b)' "$LOG" | wc -l)
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printf 'reads OK before suspend: %s\n' "$pre"
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printf 'reads OK after resume: %s\n' "$post"
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printf 'failed reads total: %s\n' "$fails"
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printf 'failed reads outside the suspend window: %s\n' "$fails_outside"
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echo
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echo "engine registers across the suspend:"
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mapfile -t REGS_AFTER < <(snapshot_regs "$BDF")
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moved=0
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for i in "${!REGS_AFTER[@]}"; do
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if [[ "${REGS_AFTER[i]}" == "${REGS_BEFORE[i]}" ]]; then
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printf ' %-28s unchanged\n' "${REGS_BEFORE[i]}"
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else
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printf ' %s -> %s CHANGED\n' "${REGS_BEFORE[i]}" "${REGS_AFTER[i]}"
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moved=$((moved + 1))
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fi
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done
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if ((moved)); then
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echo " note: something reprogrammed the engine across the suspend."
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echo " On resume the driver restores command state per transfer, but a"
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echo " change here means firmware touched it while the OS was down."
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fi
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echo
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NEW=$(dmesg | tail -n "+$((DMESG_START + 1))")
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grep -Ei 'i2c-imc-skylake|BUG:|WARNING:|Oops:|KASAN:|lockdep' <<< "$NEW" || echo "(no driver or kernel complaints)"
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echo
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rc=0
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((pre > 0)) || { echo "FAIL: no successful read before suspend"; rc=1; }
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((post > 0)) || { echo "FAIL: reads did not recover after resume"; rc=1; }
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((fails_outside == 0)) || { echo "FAIL: reads failed outside the suspend window"; rc=1; }
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grep -Eiq 'BUG:|WARNING:|Oops:|KASAN:|lockdep' <<< "$NEW" && { echo "FAIL: kernel complaint"; rc=1; }
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((rc == 0)) && echo "PASS: transfers resumed correctly and nothing complained"
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rm -f "$LOG"
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exit $rc
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