CRITICALITY

Medium

DESCRIPTION

The device is specified to support only 3-Gbps speed. Per the standard, when used with 6-Gbps capable devices, a speed negotiation sequence must take place. During speed negotiation sequence with a 6-Gbps device, the SATA controller may potentially misinterpret a valid 3-Gbps stream and attempt to establish link even though the external SATA device is sending at 6-Gbps speed. If this occurs, the link controller will be at an invalid state requiring a reset to recover.

WORKAROUND

There is no direct workaround to reliably prevent the invalid state during gen3 negotiation. For development, the user may retry multiple times to attempt to establish the link. However, a robust connection requires avoiding the 6-Gbps negotiation completely. This can be done by:

1. Use device which supports only 3-Gbps or lesser speed.
2. Use device which is configurable via jumper setting to support only 3-Gbps or lesser speed.
3. Use a device which has pre-configured non-volatile setting to support only 3-Gbps or lesser speed. Preconfigure the non-volatile speed setting offline with another device or via port multiplier which does not have such issue with 6-Gbps negotiation.
4. If the device does not support features as mentioned in 1, 2, 3, then connect to the device via a port multiplier which allows explicit configuration for 3-Gbps or lesser speed on the device side.

REVISIONS IMPACTED

SR 1.0

TDA2x: 1.0

DRA75x, DRA74x: 1.0

AM572x: 1.0