cpu: fix cpu_power=0W on Zen 5 when cpu_temp is also enabled

[Motaphe]

Fixes #1794.

Problem

On Zen 5 hardware (Ryzen 7 9800X3D, kernel 7.0.3, zenpower5-dkms-git), cpu_power reports 0W whenever cpu_temp is also present in the config. Removing cpu_temp makes power display correctly. The data is readable in sysfs — the bug is entirely in MangoHud's sensor scan logic.

Root Cause

Three bugs interact:

1. zenpower5 power label not recognised

init_cpu_power_data_zenpower() searches only for SVI2 labels (SVI2_P_Core, SVI2_P_SoC) — the interface exposed by zenpower on Zen 2/3/4. zenpower5-dkms-git (Zen 5) exposes package power as a single RAPL reading instead:

power1_label = "RAPL_P_Package"
power1_input = 41000000   # µW, ~41W at idle

Neither SVI2 label is present, so find_input fails and the function returns nullptr.

2. Unconditional break blocks the zenergy fallback

} else if (name == "zenpower") {
    cpuPowerData = (CPUPowerData*)init_cpu_power_data_zenpower(path);
    break;  // exits even if init returned nullptr

When zenpower is enumerated before zenergy, the loop exits with cpuPowerData == nullptr. zenergy exports Esocket0 cumulative energy and would succeed as a fallback, but is never reached.

3. Why it correlates with cpu_temp

GetCpuFile(), called during cpu_temp init, opens files on the zenpower hwmon node. This warms the sysfs dcache entries for that device, altering readdir() bucket order on the subsequent InitCpuPowerData() call — zenpower now appears before zenergy. Without cpu_temp, zenergy appears first and succeeds immediately. With cpu_temp, zenpower comes first, returns nullptr, the unconditional break fires, and power stays 0W for the process lifetime.

Fix

init_cpu_power_data_zenpower — try SVI2 labels first (Zen 4 and older, code path unchanged). If not found, try RAPL_P_Package. Return nullptr only if neither is present.

get_cpu_power_zenpower — drop the early-return that required both corePowerFile and socPowerFile. When socPowerFile is null (Zen 5 single-RAPL case), socPower stays 0. The destructor already null-checks socPowerFile, so teardown is unaffected.

InitCpuPowerData loop — break → if (cpuPowerData) break; so a failed zenpower init lets the loop continue to zenergy.

Backward compatibility: Zen 4 and older zenpower (SVI2 labels present) takes the original code path unchanged — the RAPL_P_Package branch is only entered when SVI2 labels are absent.

Test

CPU:    Ryzen 7 9800X3D (Zen 5)
Kernel: 7.0.3-1-cachyos
Driver: zenpower5-dkms-git

Before: MANGOHUD_CONFIG="cpu_temp,cpu_power" mangohud glxgears  →  cpu_power = 0W
After:  MANGOHUD_CONFIG="cpu_temp,cpu_power" mangohud glxgears  →  cpu_power ≈ 41W ✓

MANGOHUD_CONFIG="cpu_power" (no cpu_temp) works correctly before and after.