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Some firmware implementations incorrectly return the same altmode
multiple times at different offsets when queried via
UCSI_GET_ALTERNATE_MODES. This causes sysfs duplicate filename errors
and kernel call traces when the driver attempts to register the same
altmode twice:
sysfs: cannot create duplicate filename '/devices/.../typec/port0/port0.0/partner'
typec-thunderbolt port0-partner.1: failed to create symlinks
typec-thunderbolt port0-partner.1: probe with driver typec-thunderbolt failed with error -17
The matching rules differ by recipient:
- UCSI_RECIPIENT_CON (port) and UCSI_RECIPIENT_SOP_P (plug):
Two altmodes with identical SVID and VDO are byte-for-byte
duplicates and the second has no observable function, so drop it.
- UCSI_RECIPIENT_SOP (partner):
The typec class binds each partner altmode to a port altmode of
the same SVID via altmode_match()/device_find_child(), which
returns the first port altmode with a matching SVID. If the
partner advertises more altmodes for SVID X than the port
advertises, the surplus partner altmode(s) collapse onto an
already-paired port altmode and trigger the
"duplicate filename .../partner" sysfs error during
typec_altmode_create_links(). Use the port-side altmode count for
SVID X as the authoritative cap and reject any partner altmode
that would exceed it. This preserves legitimate multi-Mode
partner altmodes (vendor SVIDs that the port really does
advertise more than once) while filtering the firmware-generated
duplicates that have no port counterpart, and is therefore
stricter than a plain SVID+VDO comparison (which still admits the
Thunderbolt case where firmware reports the same SVID twice with
different VDOs) without being over-broad like a plain SVID match
(which would falsely drop legitimate vendor multi-Mode entries).
If a duplicate is detected, skip it and emit a clean warning instead
of generating a kernel call trace:
ucsi_acpi USBC000:00: con2: Firmware bug: duplicate partner altmode SVID 0x8087 at offset 1, ignoring.
ucsi_acpi USBC000:00: con2: VDO mismatch: 0x8087a043 vs 0x00000001
The duplicate detection logic lives in a reusable helper
ucsi_altmode_is_duplicate() and is invoked from
ucsi_register_altmodes(). It applies to all three recipient types:
partner (SOP), port (CON), and plug (SOP_P) altmodes.
Fixes:
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|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .clippy.toml | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .pylintrc | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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