Uh oh!
There was an error while loading. Please reload this page.
Continuous framebuffer refresh: display new frames as they arrive on stdin - #13
Merged
Merged
Conversation
CopilotAI
changed the title
[WIP] Add refresh functionality for framebuffer on new imageContinuous framebuffer refresh: display new frames as they arrive on stdinMay 23, 2026
eichenbergerforce-pushed
the
copilot/add-refresh-framebuffer-on-new-image
branch
from
May 23, 2026 14:52
1c0edd6 to
b856deaCompareeichenbergerforce-pushed
the
copilot/add-refresh-framebuffer-on-new-image
branch
from
May 24, 2026 13:55
6bffe8e to
f701031Compareeichenberger
marked this pull request as ready for review
May 24, 2026 13:56
eichenberger
approved these changes
May 24, 2026
There was a problem hiding this comment.
Pull request overview
This PR updates drm-framebuffer to support continuously reading frames from stdin and updating the display as each full frame arrives, and documents how to stream multiple frames and generate .fb files.
Changes:
- Refactors display logic into a helper and adds a
select()+signalfd()driven loop to read and display multiple frames fromstdin. - Updates README with a “Streaming multiple frames” example and an ImageMagick command for producing BGRA
.fbfiles.
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 6 comments.
| File | Description |
|---|---|
| README.md | Documents multi-frame streaming usage and ImageMagick conversion to .fb. |
| main.c | Implements continuous frame ingestion from stdin and signal-driven termination. |
💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.
Uh oh!
There was an error while loading. Please reload this page.
Uh oh!
There was an error while loading. Please reload this page.
Uh oh!
There was an error while loading. Please reload this page.
Uh oh!
There was an error while loading. Please reload this page.
Uh oh!
There was an error while loading. Please reload this page.
Uh oh!
There was an error while loading. Please reload this page.
ContributorAuthor
Just as a heads up, I was blocked by some firewall rules while working on your feedback. Expand below for details. Warning Firewall rules blocked me from connecting to one or more addresses (expand for details)I tried to connect to the following addresses, but was blocked by firewall rules:
If you need me to access, download, or install something from one of these locations, you can either:
|
Instead of blocking with sigwait() after displaying the first frame, use signalfd() + select() to simultaneously monitor: - stdin for new frame data - SIGINT/SIGTERM for clean shutdown When a new complete frame is received on stdin it is immediately displayed. When stdin reaches EOF the last frame stays on screen and the program continues waiting for a signal. SIGINT or SIGTERM still causes a clean exit (restoring the original CRTC state). The display logic is extracted into a separate display_framebuffer() helper to avoid duplication. Co-authored-by: Stefan Eichenberger <eichest@gmail.com>
Co-authored-by: Stefan Eichenberger <eichest@gmail.com>
…andle pitch The inner read loop used `dumb_framebuffer.size` as the number of bytes to collect before displaying a frame. The kernel's DRM_IOCTL_MODE_CREATE_DUMB may align the pitch (row stride) beyond `width * bpp/8`, making `size` (`= pitch * height`) larger than the packed pixel data users actually supply. The code would therefore block waiting for phantom padding bytes until more data arrived, causing the "need 2 KB extra" symptom. Fix: - Compute `row_stride = width * bpp/8` (packed bytes per row). - Compute `image_size = row_stride * height` (bytes the user provides). - Read row-by-row: each `read()` targets at most the remaining bytes in the current row, written to `fb->data + row * pitch + col`. This places every row at the correct pitched offset in the mapped buffer, fixing the silent display corruption that would occur when pitch > row_stride. - Stop after `image_size` bytes, so a complete frame is displayed as soon as the last pixel byte arrives, with no extra data needed. Co-authored-by: Stefan Eichenberger <eichest@gmail.com>
eichenbergerforce-pushed
the
copilot/add-refresh-framebuffer-on-new-image
branch
from
May 24, 2026 14:10
01577c0 to
8b048b6CompareUh oh!
There was an error while loading. Please reload this page.
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for freeto join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Uh oh!
There was an error while loading. Please reload this page.