Fix minor transmit stall race when in USB to CAN bridge mode #6823
Conversation
This file contains 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
KevinOConnor
force-pushed
the
work-canbridge-20250214
branch
from
6973749 to
6138a85
Compare
|
FYI, I also added an additional change to this PR - the gs_usb "echo frames" will now be sent back to the host prior to processing those frames. This helps improve the output of candump debugging logs (it should not have an impact on klipper itself). -Kevin |
Don't limit the canbus_notify_tx() wakeup to cases where notify_local is set - perform the wakeup whenever the host_status field indicates the main task has work pending. This fixes a small race condition where the main task could block sending a usb echo frame, and the canbus_send() code gets called as the usb bandwidth becomes available but before a usb wakeup notification is sent. In that situation, the usb code may not issue a wake event and the echo frames may be delayed. Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Separate code in usbcan_task() to new drain_host_queue(). Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
The Linux kernel reports a canbus message as transmitted when it gets the echo frame back. Processing the message prior to sending the echo frame can lead to odd looking debugging logs (as the response messages may appear to predate the request messages). This doesn't impact the Klipper code, but it does make analyzing logs harder. Fix by sending the echo frame prior to processing the frame. Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
KevinOConnor
force-pushed
the
work-canbridge-20250214
branch
from
6138a85 to
941fb5a
Compare
Sign up for free
to 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.
There was a small race condition that could allow transmit "echo" frames to become briefly stalled when in USB to CAN bridge mode. This would likely only effect some controllers - potentially the stm32 usbotg (stm32f4 and stm32h7 devices).
The PR also contains a couple of commits intended to better organize the usb_canbus.c code.
-Kevin