The errata description is:
Workaround for Default Duration of LFPS Handshake Signaling for
Device-Initiated U1 Exit is too short.
The default duration of the LFPS handshake generated by USB3380 for a
device-initiated U1-exit may not be
long enough for certain SuperSpeed downstream ports (SuperSpeed hubs/hosts) to
recognize. This could lead
to USB3380 entering the recovery state pre-maturely and ending up in the
SS.Inactive state.
I have observed various enumeration failures, seemingly related to
lost transactions or SETUP status phases on modern hosts (typically
thunderbolt capable systems) without this workaround.
Signed-off-by: Benjamin Herrenschmidt <b...@kernel.crashing.org>
---
- v2. Rebased on top of Felipe's tree
drivers/usb/gadget/udc/net2280.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/drivers/usb/gadget/udc/net2280.c b/drivers/usb/gadget/udc/net2280.c
index e0191146ba22..51efee21915f 100644
--- a/drivers/usb/gadget/udc/net2280.c
+++ b/drivers/usb/gadget/udc/net2280.c
@@ -2269,6 +2269,16 @@ static void usb_reinit_338x(struct net2280 *dev)
val |= 0x3 << HOT_RX_RESET_TS2;
writel(val, &dev->llregs->ll_tsn_counters_3);
+ /*
+ * AB errata. Errata 11. Workaround for Default Duration of LFPS
+ * Handshake Signaling for Device-Initiated U1 Exit is too short.
+ * Without this, various enumeration failures observed with
+ * modern superspeed hosts.
+ */
+ val = readl(&dev->llregs->ll_lfps_timers_2);
+ writel((val & 0xffff0000) | LFPS_TIMERS_2_WORKAROUND_VALUE,
+ &dev->llregs->ll_lfps_timers_2);
+
/*
* Set Recovery Idle to Recover bit:
* - On SS connections, setting Recovery Idle to Recover Fmw improves
