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Linux kernel source tree
c06e6cd488
UGREEN USB-C Multifunction Adapter Model CM512 (AKA "Revodok 107")
exposes two SVIDs: 0xff01 (DP Alt Mode) and 0x1d5c. The DISCOVER_MODES
step succeeds for 0xff01 and gets a NAK for 0x1d5c. Currently this
results in DP Alt Mode not being registered either, since the modes
are only registered once all of them have been discovered. The NAK
results in the processing being stopped and thus no Alt modes being
registered.
Improve the situation by handling the NAK gracefully and continue
processing the other modes.
Before this change, the TCPM log ends like this:
(more log entries before this)
[ 5.028287] AMS DISCOVER_SVIDS finished
[ 5.028291] cc:=4
[ 5.040040] SVID 1: 0xff01
[ 5.040054] SVID 2: 0x1d5c
[ 5.040082] AMS DISCOVER_MODES start
[ 5.040096] PD TX, header: 0x1b6f
[ 5.050946] PD TX complete, status: 0
[ 5.059609] PD RX, header: 0x264f [1]
[ 5.059626] Rx VDM cmd 0xff018043 type 1 cmd 3 len 2
[ 5.059640] AMS DISCOVER_MODES finished
[ 5.059644] cc:=4
[ 5.069994] Alternate mode 0: SVID 0xff01, VDO 1: 0x000c0045
[ 5.070029] AMS DISCOVER_MODES start
[ 5.070043] PD TX, header: 0x1d6f
[ 5.081139] PD TX complete, status: 0
[ 5.087498] PD RX, header: 0x184f [1]
[ 5.087515] Rx VDM cmd 0x1d5c8083 type 2 cmd 3 len 1
[ 5.087529] AMS DISCOVER_MODES finished
[ 5.087534] cc:=4
(no further log entries after this point)
After this patch the TCPM log looks exactly the same, but then
continues like this:
[ 5.100222] Skip SVID 0x1d5c (failed to discover mode)
[ 5.101699] AMS DFP_TO_UFP_ENTER_MODE start
(log goes on as the system initializes DP AltMode)
Cc: stable <stable@kernel.org>
Fixes:
|
||
|---|---|---|
| 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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