mirror of
https://github.com/microsoft/PowerToys.git
synced 2026-09-01 19:51:34 +02:00
baee472288
On dual-GPU laptops, Power Display stopped detecting the built-in panel
(and adjusting its brightness) when the **discrete GPU** drives the
display — it showed "can't detect the display". This fixes that by
classifying displays by **capability** (does WMI brightness work on it?)
instead of by the nominal `OutputTechnology` value, which the discrete
GPU misreports for the internal panel.
- [x] Closes: #48587
- [x] **Communication:** I've discussed this with core contributors
already. If the work hasn't been agreed, this work might be rejected
- [x] **Tests:** Added/updated and all pass
- [x] **Localization:** All end-user-facing strings can be localized (no
new user-facing strings added)
- [ ] **Dev docs:** Added/updated
- [ ] **New binaries:** Added on the required places
On a hybrid / MUX laptop, when the **discrete GPU** drives the built-in
eDP panel, `QueryDisplayConfig` reports the panel's
`DISPLAYCONFIG_VIDEO_OUTPUT_TECHNOLOGY` as `DISPLAYPORT_EXTERNAL` (`10`)
instead of the `INTERNAL` flag (`0x80000000`) it reports under the
integrated GPU. It is the *same physical panel* (same EDID) — only the
reported connector type changes with the active GPU.
PR #47740 introduced a strict classifier: `OutputTechnology` →
internal/external, then **internal → WMI-only, external → DDC/CI-only,
with no fallback**. So under the discrete GPU the built-in panel was
classified *external* and sent to DDC/CI only — but a laptop eDP panel
does not speak DDC/CI, so it was dropped and Power Display reported it
couldn't detect any monitor. (`WmiMonitorBrightness` still exposes that
panel regardless of which GPU drives it, so the panel was actually
controllable — it just never got routed to WMI.)
- **`MonitorManager`** now runs **WMI discovery first** over the full
`QueryDisplayConfig` inventory. Every display `WmiMonitorBrightness`
exposes is treated as internal (WMI-controlled); whatever WMI does
**not** claim is routed to DDC/CI. The `OutputTechnology`-based
classifier is gone.
- **`WmiController`** matches the system-wide `WmiMonitorBrightness`
results against the full inventory by `Monitor.Id`. The persisted
`Monitor.Id` is still taken from the matched `DevicePath`
(byte-identical to the DDC route and to prior releases), so saved
brightness/per-monitor settings survive upgrades.
- New **`MonitorIdentity.FromInstanceName`** reduces a WMI
`InstanceName` to the same canonical `Monitor.Id` as `FromDevicePath`;
the separate `PnpHardwareKey` helper is removed.
- **Deleted** `DisplayClassifier` and `MonitorDisplayInfo.IsInternal`
(net ~150 fewer lines).
A monitor that exposes **both** `WmiMonitorBrightness` **and** DDC/CI is
now controlled via WMI only and won't get DDC-only features (contrast /
volume / input source / color temperature / power). This is uncommon
(typical laptop panels are WMI-only; typical external monitors are
DDC-only) and is a deliberate decision: it removes the entire class of
`OutputTechnology` misclassification bugs while keeping the performance
win of not DDC-probing internal panels.
- Built the Power Display app (`PowerDisplay.csproj`) and
`PowerDisplay.Lib.UnitTests` (x64 / Debug) with MSBuild — both succeed,
including after merging latest `main` (Windows App SDK 2.2.0).
- Ran the unit test suite: **128/128 pass**, including new
`FromInstanceName` tests — the `FromInstanceName == FromDevicePath`
equivalence invariant and a concrete #48587 regression case (the BOE
panel reported as `OutputTechnology=10`).
- Traced the fix against the reporter's diagnostic logs: the panel that
previously went `OutputTechnology=10 → External → DDC → dropped` is now
claimed by WMI and controllable.
- Reviewed the diff for regressions (Monitor.Id persistence, monitor
blacklist, mirror mode, dual-internal-panel devices, external-only
desktops).
---------
Co-authored-by: Yu Leng <yuleng@microsoft.com>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
(cherry picked from commit 32ad98a0dd)