Mask USB interrupt to avoid hardware bug in OpenTitan#2100
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Can we link this with an OT issue? Otherwise I'm worried we'll loose track of it. |
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Working on it. |
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Author
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Done. lowRISC/opentitan#3388 I put it in the desc, thought that would be better than requiring people to read through comments? |
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Cool. Can you link to the issue in the comment? |
bradjc
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Sep 10, 2020
bradjc
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Sep 10, 2020
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bors r+ |
alistair23
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Sep 10, 2020
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sirchnik
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May 12, 2026
2100: Mask USB interrupt to avoid hardware bug in OpenTitan r=bradjc a=phil-levis ### Pull Request Overview USB hardware on current OT master branch seems to have interrupt bugs: running Alarms causes persistent USB CONNECTED interrupts that can't be masked from USBDEV and cause the system to hang. So this PR modifies the PLIC to enable all interrupts *except* for the USB ones. Some open PRs on OT fix this, we'll re-enable USB interrupts when they are merged. To observe this behavior, take a look at the `opentitan-alarm-causes-usb-failures` branch. This bug report came from the alarm redesign branch; separating USB interrupt handling into a separate PR seems advisable. I've entered this as an issue for OpenTitan: lowRISC/opentitan#3388 ### Testing Strategy Compiling and running the multi alarm test. ### TODO or Help Wanted None ### Documentation Updated - [X] Updated the relevant files in `/docs`, or no updates are required. ### Formatting - [X] Ran `make prepush`. Co-authored-by: Philip Levis <pal@cs.stanford.edu> Co-authored-by: Brad Campbell <bradjc5@gmail.com>
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Pull Request Overview
USB hardware on current OT master branch seems to have interrupt bugs: running Alarms causes persistent USB CONNECTED interrupts that can't be masked from USBDEV and cause the system to hang. So this PR modifies the PLIC to enable all interrupts except for the USB ones. Some open PRs on OT fix this, we'll re-enable USB interrupts when they are merged.
To observe this behavior, take a look at the
opentitan-alarm-causes-usb-failuresbranch.This bug report came from the alarm redesign branch; separating USB interrupt handling into a separate PR seems advisable.
I've entered this as an issue for OpenTitan: lowRISC/opentitan#3388
Testing Strategy
Compiling and running the multi alarm test.
TODO or Help Wanted
None
Documentation Updated
/docs, or no updates are required.Formatting
make prepush.