feat(egfx)!: surface total_frames_decoded on the frame-ack callback#1345
Merged
Benoît Cortier (CBenoit) merged 2 commits intoJun 1, 2026
Conversation
GraphicsPipelineHandler::on_frame_ack already receives frame_id and queue_depth, but handle_frame_acknowledge drops the third field the client sends in FrameAcknowledgePdu (MS-RDPEGFX 2.2.2.13): total_frames_decoded, the client's running decoded-frame count. Computing encoded_count - total_frames_decoded gives an instant measure of the client's decode backlog, which a server needs for closed-loop EGFX flow control (see issue Devolutions#790: ironrdp-web becomes unresponsive under rapid framebuffer updates because nothing throttles to the client decode rate). Extend on_frame_ack to pass total_frames_decoded through. ironrdp-egfx is unpublished, so the breaking signature change has no external SemVer impact; the only in-tree consumers are the default impl and the egfx testsuite handler, both updated here.
Greg Lamberson (glamberson)
added a commit
to lamco-admin/IronRDP
that referenced
this pull request
May 31, 2026
Mirror upstream PR Devolutions#1345: extend GraphicsPipelineHandler::on_frame_ack to pass the client's total_frames_decoded (MS-RDPEGFX 2.2.2.13), and drop the fork-only on_frame_ack_full method that carried it via a delegating default. The call-site routes through the extended on_frame_ack directly. Keeps this fork uniform with the upstream change so they converge on merge.
This was referenced Jun 1, 2026
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 free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
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Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be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.
Summary
GraphicsPipelineHandler::on_frame_ack already receives frame_id and queue_depth, but handle_frame_acknowledge drops the third field the client sends in FrameAcknowledgePdu (MS-RDPEGFX 2.2.2.13): total_frames_decoded, the client's running decoded-frame count. encoded_count - total_frames_decoded is an instant measure of the client's decode backlog, which a server needs for closed-loop EGFX flow control. Issue #790 (ironrdp-web becomes unresponsive under rapid framebuffer updates) is the user-facing symptom of having no such signal.
This extends on_frame_ack to pass total_frames_decoded through. The field is already decoded; the handler just dropped it before the callback. ironrdp-egfx is unpublished (publish = false), so the breaking signature change has no external SemVer impact; the only in-tree consumers are the trait default and the egfx testsuite handler, both updated here. ironrdp-server inherits the default and is unchanged.
Validation
cargo xtask check fmt/lints/tests/typos/locks all pass.
Notes
Breaking on the GraphicsPipelineHandler trait (hence feat!), scoped to ironrdp-egfx plus its testsuite. This surfaces the field only; it adds no flow-control policy.