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Issue #1791

[RepWifiApp] Instable interface wlan0 on i9100

Added by Fil Bergamo 6 months ago. Updated 4 months ago.

Status:
New
Priority:
Normal
Assignee:
Category:
Wi-Fi
Target version:
Start date:
04/12/2017
Due date:
% Done:

0%

Resolution:
Device:
Galaxy S 2 (I9100)

Description

Conditions:
- device: I9100
- battery level below 80%
- using RepWifi App to connect to a WiFi access point, via an external dongle (ath9k_htc)

Behaviour:
The "wlan0" interface assigned to the external dongle gets removed while interacting with the WiFi access point, causing the connection process to abort. The user needs to physically unplug and re-plug the dongle to get the interface appear again in the list returned by

ip link

The issue is almost totally absent at full battery level, raising the suspect that it could somehow have something to do with the dongle not receiving enough current. Issues with current drawing were present even on Replicant 4.2 on the i9100.

When using the scripts from the "Terminal Emulator" app or from the built-in terminal, the issue is much less frequent.
This could be related to the app being graphically more demanding than the bare terminal, and as such, being more CPU-intensive, such that it draws more current, preventing the dongle to get enough power, especially when charge is low.

A possible solution could come from looking at the source code of the built-in terminal app, to see how it manages to call shell commands, and see if using the same method in RepWifi App solves the issue (currently RepWifi launches "su" as a process and fills its standard input with commands via pipes).

History

#1 Updated by Wolfgang Wiedmeyer 4 months ago

This issue more or less also happens with the Galaxy Note and Galaxy Nexus. It's also worth to look at the kernel driver code and possibly the firmware code to identify possible ways to save power. Others who are a lot more involved with ath9k could be helpful, like OpenWRT devs.

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