Hyundai: delay cancel button send by sunnyhaibin · Pull Request #3305 · commaai/opendbc

sunnyhaibin · 2026-04-07T02:56:11Z

Description

Closes Hyundai: ACC error message when brake is used instead of pause button (2023 Ioniq 5 HDA2) #2770
On some HKG CAN and CAN FD non-CANFD_ALT_BUTTONS models, the cancel button bit (CF_Clu_CruiseSwState / CRUISE_BUTTONS = 4) is a pause/resume toggle, not a dedicated cancel. When the driver brakes to disengage, openpilot fires this bit ~17 ms later while factory SCC is still mid-transition, triggering the "SCC Conditions Not Met" alert.
carcontroller now delays the cancel button send by CANCEL_BUTTON_DELAY_FRAMES = 10 (~100 ms) using a cancel_counter pattern, same approach GM uses for its ECM soft-disable fault (thanks @sshane !). This lets factory SCC disengage naturally on brake press before OP ever sends the toggle.
The button still fires as a fallback if CC.cruiseControl.cancel remains asserted past the delay, such as factory SCC failed to disengage on brake for any other reason. Force-cancel remains fully functional.
Measured brake -> SCC-disengage latency on 161 HKG segments:
- median 31 ms
- p90 49 ms
- p99/max 100 ms
- 100% of brake-triggered disengages complete within 100 ms.

Validation

Dongle ID: 79f534ddd71804c0
Route: 00000015--738e5913fc/0

Before	After
`79f534ddd71804c0/00000011--ecef752f2c`	`79f534ddd71804c0/00000015--738e5913fc`

IMG_3059.mov	IMG_3057.mov

…rce-disengage

github-actions · 2026-04-07T03:00:25Z

Car behavior report

Replays driving segments through this PR and compares the behavior to master.
Please review any changes carefully to ensure they are expected.

Testing 260 segments for: HYUNDAI_AZERA_HEV_6TH_GEN, HYUNDAI_ELANTRA_GT_I30, HYUNDAI_ELANTRA_2021, HYUNDAI_ELANTRA_HEV_2021, HYUNDAI_GENESIS, HYUNDAI_IONIQ, HYUNDAI_IONIQ_HEV_2022, HYUNDAI_IONIQ_EV_2020, HYUNDAI_IONIQ_PHEV_2019, HYUNDAI_IONIQ_PHEV, HYUNDAI_KONA_2022, HYUNDAI_KONA_EV, HYUNDAI_KONA_EV_2022, HYUNDAI_KONA_EV_2ND_GEN, HYUNDAI_SANTA_FE, HYUNDAI_SANTA_FE_2022, HYUNDAI_SANTA_FE_HEV_2022, HYUNDAI_SANTA_FE_PHEV_2022, HYUNDAI_SONATA, HYUNDAI_SONATA_LF, HYUNDAI_STARIA_4TH_GEN, HYUNDAI_PALISADE, HYUNDAI_SONATA_HYBRID, HYUNDAI_IONIQ_5, HYUNDAI_IONIQ_6, HYUNDAI_TUCSON_4TH_GEN, HYUNDAI_SANTA_CRUZ_1ST_GEN, HYUNDAI_CUSTIN_1ST_GEN

✅ 0 changed, 260 passed, 0 errors

sunnyhaibin · 2026-04-07T05:26:21Z

Before	After
`79f534ddd71804c0/00000011--ecef752f2c`	`79f534ddd71804c0/00000015--738e5913fc`

IMG_3059.mov	IMG_3057.mov

sunnyhaibin · 2026-04-18T17:00:26Z

@sshane please let me know if there's anything else you'd want to see on this. I have been driving on this for 2 weeks and have no issue with it. Thanks!

sshane · 2026-04-18T17:21:43Z

+        # Delayed cancel: on newer CAN models, CF_Clu_CruiseSwState=4 is a pause/resume toggle (not a true cancel).
+        # Waiting CANCEL_BUTTON_DELAY_FRAMES lets factory SCC disengage naturally on brake press within its ~100 ms
+        # latency, and this branch acts as a fallback if SCC fails to disengage for any other reason.


you can remove these 2 if the top describes it

sshane

Matches GM, LGTM. This may eliminate or reduce Toyota beep, I'm not totally sure it's not just a conflict when braking. Can you make a generic function that GM and this can re-use? Or at least put up a temp commit so I can check it out?

sunnyhaibin · 2026-04-18T20:30:17Z

@sshane removed duplicated comments per review. Ready to merge.

This may eliminate or reduce Toyota beep, I'm not totally sure it's not just a conflict when braking. Can you make a generic function that GM and this can re-use? Or at least put up a temp commit so I can check it out?

I opened a draft PR here. Added Toyota in there for now for easier testing. Will split once it's confirmed to work.

car: common function for delayed factory cruise canceling #3336

commaai#3305

sshane · 2026-04-22T02:45:49Z

          if self.CP.flags & HyundaiFlags.CANFD_ALT_BUTTONS:
            can_sends.append(hyundaicanfd.create_acc_cancel(self.packer, self.CP, self.CAN, CS.cruise_info))
            self.last_button_frame = self.frame


Wouldn't these cars have the same problem? It's just a message name difference?

Oh nvm we send ACC message. Why can't we always send ACC message? No comment explaining why. Example of early complexity harming future work

Unifying this is the kind of stuff I want to do before new ports

sshane · 2026-04-22T02:49:24Z

 MAX_ANGLE_FRAMES = 89
 MAX_ANGLE_CONSECUTIVE_FRAMES = 2

+# On some HKG CAN and CAN FD non-CANFD_ALT_BUTTONS, the cancel button (CF_Clu_CruiseSwState / CRUISE_BUTTONS = 4) is


Merging now, but can you update this comment after when we figure out if we can unify CC with the CAN FD alt and non alt buttons?

Hyundai: prioritize brake over pause/cancel button for factory SCC fo…

a2ac1a2

…rce-disengage

github-actions Bot added car related to opendbc/car/ hyundai labels Apr 7, 2026

sunnyhaibin changed the title ~~Hyundai: prioritize brake over pause/cancel button for factory SCC fo…~~ Hyundai: prioritize brake over pause/cancel button for factory SCC force-disengage Apr 7, 2026

sunnyhaibin changed the title ~~Hyundai: prioritize brake over pause/cancel button for factory SCC force-disengage~~ Hyundai: prioritize brake press over pause/cancel button for force-disengage Apr 7, 2026

sshane reviewed Apr 7, 2026

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Comment thread opendbc/car/hyundai/carcontroller.py Outdated

sunnyhaibin added 2 commits April 7, 2026 00:23

try the gm method

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comment

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sunnyhaibin marked this pull request as ready for review April 7, 2026 05:13

sunnyhaibin changed the title ~~Hyundai: prioritize brake press over pause/cancel button for force-disengage~~ Hyundai: delay cancel button send prior force disengage Apr 7, 2026

sunnyhaibin added 2 commits April 7, 2026 01:20

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sunnyhaibin force-pushed the cancel-car-specific branch from 05c7819 to 45c15aa Compare April 7, 2026 05:21

Merge branch 'master' into cancel-car-specific

a55f7f8

sunnyhaibin added 3 commits April 8, 2026 02:27

Merge branch 'master' into cancel-car-specific

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Merge branch 'master' into cancel-car-specific

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Merge branch 'master' into cancel-car-specific

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sshane reviewed Apr 18, 2026

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sshane approved these changes Apr 18, 2026

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per code review

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nayan8teen added a commit to nayan8teen/opendbc that referenced this pull request Apr 19, 2026

delay cancel button send prior force disengage

a1e2d2f

commaai#3305

sshane reviewed Apr 22, 2026

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mt

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sshane reviewed Apr 22, 2026

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sshane added 2 commits April 21, 2026 19:54

cmt

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right before use

264e184

this is redund

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sshane changed the title ~~Hyundai: delay cancel button send prior force disengage~~ Hyundai: delay cancel button send Apr 22, 2026

sshane merged commit 480cde8 into commaai:master Apr 22, 2026
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sshane deleted the cancel-car-specific branch April 22, 2026 03:07

sshane mentioned this pull request Apr 25, 2026

bump opendbc commaai/openpilot#37907

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sshane merged 14 commits intocommaai:masterfrom
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