# Vangelis freeze on custom build (Resolved) **URL:** \ **Category:** Development\ **Created:** [April 19, 2026, 3:04pm UTC](https://discourse.zynthian.org/t/vangelis-freeze-on-custom-build-resolved/13038 "2026-04-19T15:04:41Z")\ **Posts on this page:** 3\ **Page:** 1

**Author:** ![smespresati](https://discourse.zynthian.org/letter_avatar_proxy/v4/letter/s/9d8465/32.png) [@smespresati](https://discourse.zynthian.org/u/smespresati)\ **Post date:** [April 19, 2026, 3:04pm UTC](https://discourse.zynthian.org/t/vangelis-freeze-on-custom-build-resolved/13038/1 "2026-04-19T15:04:41Z")

Hi guys, I’ve been fighting making my custom build to work. My hardware is: pi 5, arturia minifuse 2 otg (usb), display Minix SF10T (hdmi+usb). It’s a touch only setup. Zynthian boot from nvme and I’m using a 100 w power by Iniu. This setup works pretty well with Oram stable, then I updated to Vangelis. I can easily setup touch interface in Vangelis, but the gui freezes after a while and I’ve discovered how to reproduce the issue: unhide v5 keypad touch widget, load a snapshot, then hide v5 touch widget at this point mixer controls work, unhide v5 touch widget and then widget buttons are unresponsive, the mixer controls work until main is selected, then mixer is also unresponsive. I think others zynthianers with custom builds have reported something similar. I did all these testing with Gemini AI and follow the findings. What’s your opinion about Gemini findings? * * * **Report: RPi 5 System Deadlock on Vangelis Branch (I/O & Interrupt Saturation)** #### **1. System Environment** - **Platform:** Raspberry Pi 5 (RP1 Controller). - **Zynthian Version:** Vangelis (Branch). - **Hardware Setup:** - **Initial Comparison:** System was stable under _Oram_ (Stable). Instability/Deadlock triggers immediately after migration to _Vangelis_. #### **2. Methodology & Findings** - **Finding 1: USB Bus Saturation.** Monitoring interrupts via `cat /proc/interrupts | grep xhci` revealed a severe imbalance in IRQ distribution across the RP1 buses. - **Finding 2: Snapshot-Triggered Deadlock.** Loading a Snapshot triggers a complete system freeze. The failure is sequential and reproducible: - **Finding 3: Resource Contention (HTOP Analysis).** Analysis of `htop` during the hang shows a massive number of `python3` (`zynthian_main.py`) child processes in **`S` (Interruptible Sleep)** or **`D` (Uninterruptible I/O)** state. #### **3. Summary of Hypothesis** The instability in _Vangelis_ on the RPi 5 appears to be a **synchronous-to-asynchronous architecture conflict**. The Snapshot process and Mixer view queries are likely blocking the main event loop while waiting for audio engine state updates that are delayed by the RP1 controller’s interrupt handling. Unlike _Oram_, which seems more tolerant of these latency spikes, _Vangelis_ enters a deadlock state (likely a mutex lock or thread hang) when audio state queries are concurrent with high-traffic HID/Audio USB interrupts. #### **4. Recommendations for Developers** 1. **Audit Mixer Query Implementation:** Investigate if the GUI thread is performing synchronous blocking calls to audio engine statuses. Implementing asynchronous queries (using `asyncio` or worker threads) may prevent the GUI from deadlocking. 2. **Interrupt Handling on RP1:** Review IRQ affinity/priority handling in the _Vangelis_ kernel for the RP1 controller, as the system struggles to balance HID and Audio streams compared to previous generations. 3. **V5 Driver Resilience:** Determine why physical input drivers (V5 buttons) cease operation before the GUI freeze, as this suggests the event-polling loop is being starved by the Mixer’s blocking calls. * * * Best regards. ---

**Author:** ![riban](https://discourse.zynthian.org/user_avatar/discourse.zynthian.org/riban/32/2331_2.png) [@riban](https://discourse.zynthian.org/u/riban)\ **Post date:** [May 9, 2026, 10:40am UTC](https://discourse.zynthian.org/t/vangelis-freeze-on-custom-build-resolved/13038/2 "2026-05-09T10:40:24Z")

58 posts were merged into an existing topic: [Chain Manager screen lock up on Vangelis (Resolved)](https://discourse.zynthian.org/t/chain-manager-screen-lock-up-on-vangelis-resolved/13100) ---