From afdc3f777927ac8c8be5f362b74b8f793d7bc1bd Mon Sep 17 00:00:00 2001
From: henrygd <hank@henrygd.me>
Date: Sat, 28 Mar 2026 18:58:16 -0400
Subject: [PATCH] fix(agent): allow GPU_COLLECTOR=nvml without nvidia-smi
 (#1849)

---
 agent/gpu.go      | 11 ++++++-----
 agent/gpu_test.go | 19 +++++++++++++++++++
 2 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/agent/gpu.go b/agent/gpu.go
index 03c0783e..6e043e6f 100644
--- a/agent/gpu.go
+++ b/agent/gpu.go
@@ -542,7 +542,7 @@ func (gm *GPUManager) collectorDefinitions(caps gpuCapabilities) map[collectorSo
 	return map[collectorSource]collectorDefinition{
 		collectorSourceNVML: {
 			group:     collectorGroupNvidia,
-			available: caps.hasNvidiaSmi,
+			available: true,
 			start: func(_ func()) bool {
 				return gm.startNvmlCollector()
 			},
@@ -734,9 +734,6 @@ func NewGPUManager() (*GPUManager, error) {
 	}
 	var gm GPUManager
 	caps := gm.discoverGpuCapabilities()
-	if !hasAnyGpuCollector(caps) {
-		return nil, fmt.Errorf(noGPUFoundMsg)
-	}
 	gm.GpuDataMap = make(map[string]*system.GPUData)
 
 	// Jetson devices should always use tegrastats (ignore GPU_COLLECTOR).
@@ -745,7 +742,7 @@ func NewGPUManager() (*GPUManager, error) {
 		return &gm, nil
 	}
 
-	// if GPU_COLLECTOR is set, start user-defined collectors.
+	// Respect explicit collector selection before capability auto-detection.
 	if collectorConfig, ok := utils.GetEnv("GPU_COLLECTOR"); ok && strings.TrimSpace(collectorConfig) != "" {
 		priorities := parseCollectorPriority(collectorConfig)
 		if gm.startCollectorsByPriority(priorities, caps) == 0 {
@@ -754,6 +751,10 @@ func NewGPUManager() (*GPUManager, error) {
 		return &gm, nil
 	}
 
+	if !hasAnyGpuCollector(caps) {
+		return nil, fmt.Errorf(noGPUFoundMsg)
+	}
+
 	// auto-detect and start collectors when GPU_COLLECTOR is unset.
 	if gm.startCollectorsByPriority(gm.resolveLegacyCollectorPriority(caps), caps) == 0 {
 		return nil, fmt.Errorf(noGPUFoundMsg)
diff --git a/agent/gpu_test.go b/agent/gpu_test.go
index ade17d91..d595ab1b 100644
--- a/agent/gpu_test.go
+++ b/agent/gpu_test.go
@@ -1461,6 +1461,25 @@ func TestNewGPUManagerConfiguredCollectorsMustStart(t *testing.T) {
 	})
 }
 
+func TestCollectorDefinitionsNvmlDoesNotRequireNvidiaSmi(t *testing.T) {
+	gm := &GPUManager{}
+	definitions := gm.collectorDefinitions(gpuCapabilities{})
+	require.Contains(t, definitions, collectorSourceNVML)
+	assert.True(t, definitions[collectorSourceNVML].available)
+}
+
+func TestNewGPUManagerConfiguredNvmlBypassesCapabilityGate(t *testing.T) {
+	dir := t.TempDir()
+	t.Setenv("PATH", dir)
+	t.Setenv("BESZEL_AGENT_GPU_COLLECTOR", "nvml")
+
+	gm, err := NewGPUManager()
+	require.Nil(t, gm)
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "no configured GPU collectors are available")
+	assert.NotContains(t, err.Error(), noGPUFoundMsg)
+}
+
 func TestNewGPUManagerJetsonIgnoresCollectorConfig(t *testing.T) {
 	dir := t.TempDir()
 	t.Setenv("PATH", dir)