(0.15.x) wait for LEDs output to finish before OS calls that potentially suspend interrupts by softhack007 · Pull Request #5435 · wled/WLED

softhack007 · 2026-03-21T21:49:17Z

Add a short wait time before calling file.close() and ESP.getFreeHeap(), to prevent LED glitches caused by interrupt stalls.

potential fix for #5427

Summary by CodeRabbit

Bug Fixes
- Enhanced timing synchronization between system operations (file access, memory queries, OTA updates, file uploads) and LED transmission cycles to prevent timing conflicts with addressable LED strips.
- Improved trigger event handling to prevent event loss during LED service suspension.

f.close() writes buffered data to flash, and shortly suspends all other interrupts during writing. This can lead to LEDs flickering, especially on 8266 or -C3 that don't have the RMTHI driver.

reduces code duplication

two more places where flickering can be reduced

coderabbitai · 2026-03-21T21:49:23Z

Important

Review skipped

Auto reviews are disabled on base/target branches other than the default branch.

Please check the settings in the CodeRabbit UI or the .coderabbit.yaml file in this repository. To trigger a single review, invoke the @coderabbitai review command.

⚙️ Run configuration

Configuration used: Repository UI

Review profile: CHILL

Plan: Pro

Run ID: b6ddd9c4-91eb-4a26-8c42-3efcf44f7f36

You can disable this status message by setting the reviews.review_status to false in the CodeRabbit configuration file.

Use the checkbox below for a quick retry:

✅ Review completed - (🔄 Check again to review again)

✨ Finishing Touches

🧪 Generate unit tests (beta)

Create PR with unit tests
Commit unit tests in branch 8266_wait_b4_close

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

only in async paths (webserver context)

to prevent repeated attempts to close a closed file handle.

wled00/file.cpp

I overlooked that this method already existed -> merged both definitions.

wled00/file.cpp

if strip.suspend() was received in the middle of effect rendering, the final strip.show() is skipped => trigger request should not reset if suspended.

* remove statements for 8266 - 8266 UART output is not affected by paused interrupts * add statement for risc-v boards

avoids random LED flashing during OTA This is only partly related to the PR scope, but its a good idea any way so I added it here

* only resume if suspended by OTA * remove resume() from unrelated path

wled00/wled_server.cpp

suspend/resume is already handled internally in ota_update.cpp

wled00/file.cpp

* presets.json sending via webserver * cfg.json copy / compare / restore

softhack007 added 6 commits March 21, 2026 21:09

wait for LEDs output to complete before file writing

5cc289a

f.close() writes buffered data to flash, and shortly suspends all other interrupts during writing. This can lead to LEDs flickering, especially on 8266 or -C3 that don't have the RMTHI driver.

wait before ESP.getFreeHeap() - main loop

decd338

adding strip.waitForLEDs(waitMS)

2940601

reduces code duplication

use strip.waitForLEDs()

9f9e440

wait before file close (upload) and before getFreeHeap() (json info)

11304af

two more places where flickering can be reduced

restore lost comment

9e7f553

softhack007 changed the title ~~wait for LEDs output to finish before OS calls that potentially suspend interrupts~~ (0.15.x) wait for LEDs output to finish before OS calls that potentially suspend interrupts Mar 21, 2026

softhack007 added 2 commits March 21, 2026 22:52

typo

b2a27d9

comment clarification

05aeae3

This comment was marked as off-topic.

Sign in to view

prevent that strip.service() runs again after waiting

29aff99

only in async paths (webserver context)

softhack007 requested review from DedeHai and willmmiles March 21, 2026 22:29

This comment was marked as resolved.

Sign in to view

closeFile() should always consume doCloseFile flag

4495133

to prevent repeated attempts to close a closed file handle.

This comment was marked as resolved.

Sign in to view

softhack007 added 2 commits March 22, 2026 00:02

typo's in comments

d835254

comment fix

1b752ad

softhack007 commented Mar 22, 2026

View reviewed changes

wled00/file.cpp Show resolved Hide resolved

Merge branch '0_15_x' into 8266_wait_b4_close

fe2cae6

This comment was marked as resolved.

Sign in to view

remove duplicate non-const method

d9bef17

I overlooked that this method already existed -> merged both definitions.

softhack007 added this to the 0.15.5 milestone Mar 22, 2026

willmmiles reviewed Mar 22, 2026

View reviewed changes

wled00/file.cpp Outdated Show resolved Hide resolved

avoid losing "trigger" events due to strip.suspend

01520cb

if strip.suspend() was received in the middle of effect rendering, the final strip.show() is skipped => trigger request should not reset if suspended.

This comment was marked as off-topic.

Sign in to view

clarify comment

3ab8302

* remove statements for 8266 - 8266 UART output is not affected by paused interrupts * add statement for risc-v boards

This comment was marked as off-topic.

Sign in to view

suspends effects during OTA upload

4566052

avoids random LED flashing during OTA This is only partly related to the PR scope, but its a good idea any way so I added it here

This comment was marked as resolved.

Sign in to view

bugfix: OTA suspend

e1123ec

* only resume if suspended by OTA * remove resume() from unrelated path

softhack007 commented Mar 23, 2026

View reviewed changes

wled00/wled_server.cpp Outdated Show resolved Hide resolved

softhack007 added 2 commits March 23, 2026 11:33

revert OTA request handler changes

023e348

suspend/resume is already handled internally in ota_update.cpp

add short wait after OTA has suspended effects

d0c63be

This comment was marked as duplicate.

Sign in to view

softhack007 commented Mar 23, 2026

View reviewed changes

wled00/file.cpp Show resolved Hide resolved

add flicker protection before potentially longer file operations

a74d11f

* presets.json sending via webserver * cfg.json copy / compare / restore

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

(0.15.x) wait for LEDs output to finish before OS calls that potentially suspend interrupts#5435

(0.15.x) wait for LEDs output to finish before OS calls that potentially suspend interrupts#5435
softhack007 wants to merge 21 commits into0_15_xfrom
8266_wait_b4_close

softhack007 commented Mar 21, 2026 •

edited by coderabbitai bot

Loading

Uh oh!

coderabbitai bot commented Mar 21, 2026 •

edited

Loading

Review skipped

Uh oh!

This comment was marked as off-topic.

Uh oh!

This comment was marked as resolved.

Uh oh!

This comment was marked as resolved.

Uh oh!

Uh oh!

This comment was marked as resolved.

Uh oh!

Uh oh!

This comment was marked as off-topic.

Uh oh!

This comment was marked as off-topic.

Uh oh!

This comment was marked as resolved.

Uh oh!

Uh oh!

This comment was marked as duplicate.

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

Uh oh!

Conversation

softhack007 commented Mar 21, 2026 • edited by coderabbitai bot Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Summary by CodeRabbit

Uh oh!

coderabbitai bot commented Mar 21, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Review skipped

Uh oh!

This comment was marked as off-topic.

Uh oh!

This comment was marked as resolved.

Uh oh!

This comment was marked as resolved.

Uh oh!

Uh oh!

This comment was marked as resolved.

Uh oh!

Uh oh!

This comment was marked as off-topic.

Uh oh!

This comment was marked as off-topic.

Uh oh!

This comment was marked as resolved.

Uh oh!

Uh oh!

This comment was marked as duplicate.

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

softhack007 commented Mar 21, 2026 •

edited by coderabbitai bot

Loading

coderabbitai bot commented Mar 21, 2026 •

edited

Loading