qmk/qmk_firmware

[Bug] OLED does not time out when writing to last column

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#18,983 opened on Nov 7, 2022

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bughelp wanted

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Description

Describe the Bug

So I'm not entirely sure why this happens, but it seems like writing to the last row on my 128x32 OLED display prevents the OLED timeout from kicking in. I'm specifically talking about these lines.

Using oled_set_cursor(1, 13); instead of oled_set_cursor(1, 15); fixes the issue. The display times out correctly without any issues.

I've implemented a manual timeout, which fixes the issue for me, but I was curious if I'm doing something wrong or if there was an issue with QMK here.

One interesting thing I noticed is that writing with oled_write_P into the last row seems to also clip the top of the screen, so maybe the issue is with the "last row" not being a full row? I feel like that still shouldn't prevent the OLED timeout but at least it's an indication that I might be doing something wrong?

Keyboard Used

https://github.com/chrisduerr/qmk_firmware/tree/09bc1696a9410c021cf338708e2ec47912e93a68/keyboards/undeadsplit (updated to the latest QMK upstream like 1-2 weeks ago)

Contributor guide

Research direction
Investigate the OLED driver timeout mechanism. Check if writing to the last column or row resets the timeout incorrectly due to an off by one error in cursor position bounds. Look at the oled write P function and oled timeout checking logic.
Tech stack
c
Domain
embedded iot
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
CGit
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40