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| author | RD Babiera <rdbabiera@google.com> | 2023-07-31 16:59:23 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-08-23 11:10:53 +0200 |
| commit | c97cd0b4b54eb42aed7f6c3c295a2d137f6d2416 (patch) | |
| tree | a9b3a14fba117325152d3dd66f18ef0d649c6757 /drivers/fpga/tests/fpga-bridge-test.c | |
| parent | e16d5f1447e0fae6cbcd1d430b20f87b65f25307 (diff) | |
usb: typec: tcpm: set initial svdm version based on pd revision
When sending Discover Identity messages to a Port Partner that uses Power
Delivery v2 and SVDM v1, we currently send PD v2 messages with SVDM v2.0,
expecting the port partner to respond with its highest supported SVDM
version as stated in Section 6.4.4.2.3 in the Power Delivery v3
specification. However, sending SVDM v2 to some Power Delivery v2 port
partners results in a NAK whereas sending SVDM v1 does not.
NAK messages can be handled by the initiator (PD v3 section 6.4.4.2.5.1),
and one solution could be to resend Discover Identity on a lower SVDM
version if possible. But, Section 6.4.4.3 of PD v2 states that "A NAK
response Should be taken as an indication not to retry that particular
Command."
Instead, we can set the SVDM version to the maximum one supported by the
negotiated PD revision. When operating in PD v2, this obeys Section
6.4.4.2.3, which states the SVDM field "Shall be set to zero to indicate
Version 1.0." In PD v3, the SVDM field "Shall be set to 01b to indicate
Version 2.0."
Fixes: c34e85fa69b9 ("usb: typec: tcpm: Send DISCOVER_IDENTITY from dedicated work")
Cc: stable@vger.kernel.org
Signed-off-by: RD Babiera <rdbabiera@google.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20230731165926.1815338-1-rdbabiera@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/fpga/tests/fpga-bridge-test.c')
0 files changed, 0 insertions, 0 deletions