i/hdmi-cec: add a new `hdmi-cec` interface by saviq-work · Pull Request #17726 · canonical/snapd

saviq-work · 2026-09-28T15:50:57Z

The device list comes from an analysis of the different adapter code in https://github.com/Pulse-Eight/libcec/tree/master/src/libcec/adapter.

saviq-work · 2026-09-28T15:51:31Z

Corresponding documentation: canonical/snap-docs#606

github-actions · 2026-09-28T16:04:07Z

Thu Oct 15 18:37:09 UTC 2026
The following results are from: https://github.com/canonical/snapd/actions/runs/38700759149

Test Predictor Analysis

Executing

Test	Success %
openstack-arm:ubuntu-24.04-arm-64:tests/main/interfaces-system-observe	🟢 85.9%

Skipped tests from snapd-testing-skip

If you wish to have any of the below tests run in your PR, in your PR description, add 'unskip:' followed by a copy-and-pasted list of the below tests you wish to run (unskip plus test list must be valid yaml)

garden:fedora-44-64:tests/main/network-retry
garden:ubuntu-24.04-64:tests/main/apparmor-prompting-support
garden:ubuntu-24.04-64:tests/main/auto-refresh-retry
garden:ubuntu-24.04-64:tests/main/network-retry
garden:ubuntu-26.04-64:tests/main/apparmor-prompting-support
garden:ubuntu-26.04-64:tests/main/auto-refresh-retry
garden:ubuntu-26.04-64:tests/main/network-retry
openstack-arm:ubuntu-24.04-arm-64:tests/main/i18n
openstack-arm:ubuntu-24.04-arm-64:tests/main/lxd
openstack-arm:ubuntu-core-24-arm-64:tests/main/i18n
openstack-arm:ubuntu-core-24-arm-64:tests/main/lxd
openstack:debian-sid-64:tests/main/interfaces-network-status-classic
openstack:debian-sid-64:tests/main/interfaces-xdg-portal-permission-store
openstack:fedora-44-64:tests/main/network-retry
openstack:opensuse-16.0-64:tests/main/interfaces-packagekit-control
openstack:opensuse-tumbleweed-64:tests/main/interfaces-packagekit-control
openstack:opensuse-tumbleweed-selinux-64:tests/main/interfaces-packagekit-control
openstack:ubuntu-16.04-64:tests/main/lxd
openstack:ubuntu-18.04-64:tests/main/lxd
openstack:ubuntu-20.04-64:tests/main/lxd
openstack:ubuntu-22.04-64:tests/main/lxd
openstack:ubuntu-24.04-64:tests/main/apparmor-prompting-flag-restart
openstack:ubuntu-24.04-64:tests/main/apparmor-prompting-integration-tests
openstack:ubuntu-24.04-64:tests/main/apparmor-prompting-prompt-restoration
openstack:ubuntu-24.04-64:tests/main/apparmor-prompting-smoke
openstack:ubuntu-24.04-64:tests/main/apparmor-prompting-snapd-startup
openstack:ubuntu-24.04-64:tests/main/apparmor-prompting-support
openstack:ubuntu-24.04-64:tests/main/auto-refresh-retry
openstack:ubuntu-24.04-64:tests/main/i18n
openstack:ubuntu-24.04-64:tests/main/interfaces-requests-activates-handlers
openstack:ubuntu-24.04-64:tests/main/lxd
openstack:ubuntu-24.04-64:tests/main/network-retry
openstack:ubuntu-26.04-64:tests/main/apparmor-prompting-flag-restart
openstack:ubuntu-26.04-64:tests/main/apparmor-prompting-integration-tests
openstack:ubuntu-26.04-64:tests/main/apparmor-prompting-prompt-restoration
openstack:ubuntu-26.04-64:tests/main/apparmor-prompting-smoke
openstack:ubuntu-26.04-64:tests/main/apparmor-prompting-snapd-startup
openstack:ubuntu-26.04-64:tests/main/apparmor-prompting-support
openstack:ubuntu-26.04-64:tests/main/auto-refresh-retry
openstack:ubuntu-26.04-64:tests/main/i18n
openstack:ubuntu-26.04-64:tests/main/interfaces-requests-activates-handlers
openstack:ubuntu-26.04-64:tests/main/lxd
openstack:ubuntu-26.04-64:tests/main/network-retry
openstack:ubuntu-26.10-64:tests/main/apparmor-prompting-flag-restart
openstack:ubuntu-26.10-64:tests/main/apparmor-prompting-integration-tests
openstack:ubuntu-26.10-64:tests/main/apparmor-prompting-prompt-restoration
openstack:ubuntu-26.10-64:tests/main/apparmor-prompting-smoke
openstack:ubuntu-26.10-64:tests/main/apparmor-prompting-snapd-startup
openstack:ubuntu-26.10-64:tests/main/apparmor-prompting-support
openstack:ubuntu-26.10-64:tests/main/interfaces-requests-activates-handlers
openstack:ubuntu-26.10-64:tests/main/lxd
openstack:ubuntu-core-18-64:tests/main/lxd
openstack:ubuntu-core-20-64:tests/main/lxd
openstack:ubuntu-core-22-64:tests/main/lxd
openstack:ubuntu-core-24-64:tests/main/lxd
openstack:ubuntu-core-26-64:tests/main/lxd

codecov · 2026-09-28T16:38:43Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.26%. Comparing base (485d704) to head (fc421d9).
⚠️ Report is 77 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #17726      +/-   ##
==========================================
+ Coverage   77.93%   82.26%   +4.32%     
==========================================
  Files        1406     1420      +14     
  Lines      200507   202694    +2187     
  Branches     2503     2626     +123     
==========================================
+ Hits       156275   166738   +10463     
+ Misses      34866    33836    -1030     
+ Partials     9366     2120    -7246

Flag	Coverage Δ
unittests	`82.26% <100.00%> (+4.32%)`	⬆️

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Copilot

Copilot review overview

🟡 Changes recommended

Pulse-Eight USB adapters remain unsupported, and /dev/vchiq is omitted from device-cgroup tagging.

Review effort: Balanced
Findings: 1

Open (1)

Allow Pulse-Eight USB-CEC adapters and USB device discovery · New

What changed in this PR

Adds an hdmi-cec built-in interface for confined access to HDMI-CEC adapters.

Changes:

Defines AppArmor, udev, and base-declaration policy.
Adds interface unit tests.
Adds a policy-test consumer application.

File	Description
`interfaces/builtin/hdmi_cec.go`	Implements the interface policy.
`interfaces/builtin/hdmi_cec_test.go`	Tests registration and generated policy.
`tests/lib/snaps/test-snapd-policy-app-consumer/meta/snap.yaml`	Adds the interface to policy integration testing.

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bboozzoo

LGTM

bboozzoo · 2026-10-08T08:15:19Z

+
+func init() {
+	registerIface(&commonInterface{
+		name:                  "hdmi-cec",


@pedronis have a look at the naming here

Yeah I was considering hdmi-cec-control, but there can't be an observe to match it…

Copilot

🟡 Changes recommended

The VCHIQ grant crosses hardware boundaries and, if retained, lacks required device-cgroup tagging.

1 open finding

hdmi-cec grants unintended camera and graphics access · New

1 resolved since last review

Allow Pulse-Eight USB-CEC adapters and USB device discovery

Previously missed (1)

In code that hasn't changed since last review

udev allowlist omits vchiq device rule

interfaces/builtin/hdmi_cec.go:59

If the /dev/vchiq route is retained after resolving its shared-device implications, this udev allowlist also needs KERNEL=="vchiq". Without that tag, strict snaps do not get the node in their device cgroup, so the Raspberry Pi/libCEC path remains unusable despite the AppArmor grant. Add the rule and cover it in TestUDevSpec, as the camera and opengl interfaces do.

🧠 Review effort: Balanced

Meulengracht

thank you, still needs a +1 from @jslarraz

jslarraz

Added some questions / requests around /dev/vchiq rw,

These give too broad access to the VideoCore subsystem, and is not needed for modern CEC support on the Raspberry Pi, handled through standard `/dev/cecX` nodes.

jslarraz

Thanks, LGTM now

saviq-work · 2026-10-13T18:09:09Z

Don't think I caused either of these?

FAIL	github.com/snapcore/snapd/daemon	91.917s
Some of the repositories have not been refreshed because of an error.

bboozzoo · 2026-10-14T07:40:43Z

Don't think I caused either of these?

FAIL	github.com/snapcore/snapd/daemon	91.917s
Some of the repositories have not been refreshed because of an error.

Yes, likely unrelated. The PR has sufficient number of approvals, I'll try to get it landed

saviq-work force-pushed the MIRENG-2199-hdmi-cec-interface branch 2 times, most recently from 20b0539 to 98cd432 Compare September 28, 2026 16:14

i/hdmi-cec: add a new hdmi-cec interface

150de6b

saviq-work force-pushed the MIRENG-2199-hdmi-cec-interface branch from 98cd432 to 150de6b Compare September 29, 2026 09:40

bboozzoo reviewed Oct 5, 2026

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Comment thread interfaces/builtin/hdmi_cec.go

bboozzoo requested review from Meulengracht and jslarraz and a balanced review from Copilot October 5, 2026 10:05

bboozzoo added the Needs security review Can only be merged once security gave a :+1: label Oct 5, 2026

bboozzoo added this to the 2.79 milestone Oct 5, 2026

Copilot started reviewing on behalf of bboozzoo October 5, 2026 10:06

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Copilot AI reviewed Oct 5, 2026

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Comment thread interfaces/builtin/hdmi_cec.go

i/hdmi-cec: add a unit test the base declaration

070341b

saviq-work mentioned this pull request Oct 7, 2026

frame: add optional HDMI-CEC device handling canonical/ubuntu-frame#352

Merged

bboozzoo approved these changes Oct 8, 2026

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Meulengracht requested a balanced review from Copilot October 13, 2026 07:04

Copilot started reviewing on behalf of Meulengracht October 13, 2026 07:05

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Copilot AI reviewed Oct 13, 2026

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Comment thread interfaces/builtin/hdmi_cec.go Outdated

Meulengracht approved these changes Oct 13, 2026

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github-actions Bot added the Auto rerun spread Auto reruns spread up to 4 times in non-draft PRs w/ >=1 approval and <20 fails in any fund. system label Oct 13, 2026

jslarraz requested changes Oct 13, 2026

View reviewed changes

Comment thread interfaces/builtin/hdmi_cec.go Outdated

i/hdmi_cec: drop vchiq nodes

fc421d9

These give too broad access to the VideoCore subsystem, and is not needed for modern CEC support on the Raspberry Pi, handled through standard `/dev/cecX` nodes.

jslarraz approved these changes Oct 13, 2026

View reviewed changes

jslarraz removed the Needs security review Can only be merged once security gave a :+1: label Oct 13, 2026

bboozzoo self-assigned this Oct 14, 2026

bboozzoo closed this Oct 15, 2026

bboozzoo reopened this Oct 15, 2026

bboozzoo merged commit e6b1a1f into canonical:master Oct 15, 2026
1069 of 1103 checks passed

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