reconcile all nvidiadrivers when any nvidiadriver is changed

[rahulait]

Description

Fixes: #2259

Issue

When multiple NVIDIADriver CRs exist, conflict validation is global (overlapping node selection across all driver CRs). A common case is the default CR (no nodeSelector) selecting all GPU nodes, which blocks custom CRs with targeted selectors.
Blocked CRs currently exit reconcile from the validation path with no requeue, so they remain stuck until an external event re-triggers them.
Deleting the conflicting default CR changes global validity, but previously only the deleted object was enqueued by the primary watch, so remaining CRs were not retried immediately.

Options Considered

Option 1 (implemented):

On NVIDIADriver events, enqueue reconcile for all NVIDIADriver CRs via TypedEnqueueRequestsFromMapFunc (fan-out).

Option 2 (not implemented):

Return error from validation failure so each conflicting CR self-requeues via the rate-limiter.
Basically here. switch from nil to error:

gpu-operator/controllers/nvidiadriver_controller.go

Line 151 in d5750f2

return reconcile.Result{}, nil

Why Option 1

• Retries happen when global conflict state actually changes (create/update/delete of relevant CRs), which is the right signal.
• Avoids continuous error-driven retry loops while conflict is expected/user-caused.
• Reduces log noise and unnecessary reconcile churn, especially with many conflicting CRs and MaxConcurrentReconciles=1.
• Provides immediate unstick behavior after deleting the blocking CR, without waiting for backoff retry windows.

Why Option 2 is less useful

• Treats a configuration conflict as a transient controller failure, causing repeated retries that usually cannot succeed until user action.
• Generates sustained error logs and queue pressure; with single-worker reconcile this can delay useful work for other requests.
• Many conflicting CRs could keep that single worker busy with repeated retries.
• Converges eventually, but less efficiently and with poorer operational signal-to-noise.

Expected Outcome

After removing a conflicting NVIDIADriver (for example, deleting default CR), remaining previously blocked CRs are automatically revalidated and can proceed without manual nudges.

Checklist

• No secrets, sensitive information, or unrelated changes
• Lint checks passing (make lint)
• Generated assets in-sync (make validate-generated-assets)
• Go mod artifacts in-sync (make validate-modules)
• Test cases are added for new code paths

Testing

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[rahulait]

/ok to test 6497fe8

[karthikvetrivel]

This mostly looks good to me, Rahul. Have you tested the case where instead of deleting the default CR, you edit it to narrow the scope to limit overlap with a new, custom CR?

[rahulait]

This mostly looks good to me, Rahul. Have you tested the case where instead of deleting the default CR, you edit it to narrow the scope to limit overlap with a new, custom CR?

Yup, I tested this scenario as well and it works fine. Tested by having 3 node cluster with default nvd, then adding two more nvds targetting individual nodes and then limiting scope of default to one node. All nvds were able to bring up drivers correctly on each node.

# kubectl get nvidiadriver
NAME          STATUS   AGE
default       ready    2026-04-01T14:36:54Z
demo-gold     ready    2026-04-01T14:45:44Z
demo-silver   ready    2026-04-01T14:45:44Z