backends/drm: don't update outputs from within DrmGpu

DrmBackend::updateOutputs may delete DrmGpu objects, so calling it from within
a DrmGpu method can cause problems

BUG: 483008
FIXED-IN: 6.1.0

src/backends/drm/drm_backend.cpp

@@ -95,8 +95,11 @@ bool DrmBackend::initialize()
         }
     });
     connect(m_session, &Session::deviceResumed, this, [this](dev_t deviceId) {
-        if (const auto gpu = findGpu(deviceId)) {
+        if (const auto gpu = findGpu(deviceId); gpu && !gpu->isActive()) {
             gpu->setActive(true);
+            // the output list might've changed while the device was inactive
+            // note that this might delete the gpu!
+            updateOutputs();
         }
     });
 

src/backends/drm/drm_gpu.cpp

@@ -718,8 +718,6 @@ void DrmGpu::setActive(bool active)
             for (const auto &output : std::as_const(m_drmOutputs)) {
                 output->renderLoop()->uninhibit();
             }
-            // while the session was inactive, the output list may have changed
-            m_platform->updateOutputs();
             for (const auto &output : std::as_const(m_drmOutputs)) {
                 // force a modeset with legacy, we can't reliably know if one is needed
                 if (!atomicModeSetting()) {