ERR006308
Chip Errata for the i.MX 6Dual/6Quad and i.MX 6DualPlus/6QuadPlus, Rev. 6.1, 06/2016
214
NXP Semiconductors
Description:
The USB host core operating in streaming mode might underrun while sending the data packet of
an OUT transaction. The host then retries the OUT transaction according to the USB specification.
This issue occurs during the OUT retry. The USB host might hang on OUT retry if the data buffer
start address is not 4-byte aligned.
This applies to both the host controller and the OTG controller in host mode.
Projected Impact:
Host controller only transmits SOF packets. All other traffic is blocked.
Workarounds:
• Set the host TXFIFO threshold to a large value (TXFIFOTHRES in the TXFILLTUNING
register). This increases the tolerance to bus latency and avoids a FIFO underrun.
• Set the Stream Disable bit (SDIS) to 1 in the USBMODE register. This forces the controller to
load an entire packet in the FIFO before starting to transmit on the USB bus. Hence, the FIFO
never underruns. This somewhat reduces the maximum bandwidth of the USB, because there is
idle time when the controller waits for the entire packet to be loaded.
Proposed Solution:
No fix scheduled.
Linux BSP Status:
Software workaround implemented in Linux BSP codebase starting in release L3.0.35_4.0.0
ERR006308
USB: Host non-doubleword –aligned buffer address can cause host
to hang on OUT Retry