Hi,
I am currently testing the download from a Halcyon Symbios device using a BLE connection, and I noticed very frequent timeouts. To compare, the same code works very reliably with Shearwater devices, I own also a Perdix and a Petrel 2.
I noticed the timeout is the same for Halcyon Symbios and Shearwater:
https://github.com/libdivecomputer/libdivecomputer/blob/4f5abbddc66843c83fa…https://github.com/libdivecomputer/libdivecomputer/blob/4f5abbddc66843c83fa…
```
// Set the timeout for receiving data (3000ms).
status = dc_iostream_set_timeout (device->iostream, 3000);
```
In my tests, the Halcyon device often timeouts immediately while negotiating the connection:
```
2025-12-28 17:17:49.451313+0100 0x90987 Info 0x0 36508 0 DiveComputerApp: [codes.swiftdivecomputer:Device] Connecting to device: C4037FA6-7E9F-962F-79AF-1F4978C8A443
2025-12-28 17:17:49.452269+0100 0x90987 Info 0x0 36508 0 DiveComputerApp: [codes.swiftdivecomputer:Device] Successfully opened device: C4037FA6-7E9F-962F-79AF-1F4978C8A443
2025-12-28 17:17:52.661264+0100 0x90991 Error 0x0 36508 0 DiveComputerApp: [codes.swiftdivecomputer:Device] Download failed with status: Timeout (-7)
2025-12-28 17:17:52.661388+0100 0x90987 Info 0x0 36508 0 DiveComputerApp: [codes.swiftdivecomputer:Device] Disconnecting from device: C4037FA6-7E9F-962F-79AF-1F4978C8A443
```
or after downloading the first dive:
```
2025-12-28 17:17:05.026093+0100 0x904fa Info 0x0 36165 0 DiveComputerApp: [codes.swiftdivecomputer:Device] Connecting to device: C4037FA6-7E9F-962F-79AF-1F4978C8A443
2025-12-28 17:17:05.027610+0100 0x904fa Info 0x0 36165 0 DiveComputerApp: [codes.swiftdivecomputer:Device] Successfully opened device: C4037FA6-7E9F-962F-79AF-1F4978C8A443
2025-12-28 17:17:11.716335+0100 0x904fb Debug 0x0 36165 0 DiveComputerApp: [codes.swiftdivecomputer:Device] Dive callback called: size=12524, downloaded so far=0, maxDives=Optional(3)
2025-12-28 17:17:11.725085+0100 0x904fb Debug 0x0 36165 0 DiveComputerApp: [codes.swiftdivecomputer:Device] Dive processed successfully, returning 1 (continue)
2025-12-28 17:17:16.944712+0100 0x904fb Error 0x0 36165 0 DiveComputerApp: [codes.swiftdivecomputer:Device] Download failed with status: Timeout (-7)
2025-12-28 17:17:16.944939+0100 0x904fa Info 0x0 36165 0 DiveComputerApp: [codes.swiftdivecomputer:Device] Disconnecting from device: C4037FA6-7E9F-962F-79AF-1F4978C8A443
```
From various tests, it looks like Symbios often requires up to 5s. I changed the timeout to 10s and it works quite reliably now. In my binding I implemented the `set_timeout` callback to set the timeout specifically for this device type, so that I don't need to change/customize the libdivecomputer C source code and maintain a fork.
However, I am wondering if this is a change you would be interested to apply directly to the libdivecomputer C code, considering you have per-device timeouts. If so, I can likely provide a patch.
Let me know what do you think. And thanks for the amazing lib!
Best,
-- Simone
