This is a note to let you know that I've just added the patch titled soundwire: cadence: fix ACK/NAK handling to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: soundwire-cadence-fix-ack-nak-handling.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 1d91a85c084a096b4ff70eaa1e22704d106c480f Author: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx> Date: Fri Jan 15 13:37:37 2021 +0800 soundwire: cadence: fix ACK/NAK handling [ Upstream commit db9d9f944f95e7f3aa60ac00cbd502415152c421 ] The existing code reports a NAK only when ACK=0 This is not aligned with the SoundWire 1.x specifications. Table 32 in the SoundWire 1.2 specification shows that a Device shall not set NAK=1 if ACK=1. But Table 33 shows the Combined Response may very well be NAK=1/ACK=1, e.g. if another Device than the one addressed reports a parity error. NAK=1 signals a 'Command_Aborted', regardless of the ACK bit value. Move the tests for NAK so that the NAK=1/ACK=1 combination is properly detected according to the specification. Fixes: 956baa1992f9a ('soundwire: cdns: Add sdw_master_ops and IO transfer support') Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx> Signed-off-by: Bard Liao <yung-chuan.liao@xxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20210115053738.22630-5-yung-chuan.liao@xxxxxxxxxxxxxxx Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/soundwire/cadence_master.c b/drivers/soundwire/cadence_master.c index e3d06330d1258..f7d0f63921dc2 100644 --- a/drivers/soundwire/cadence_master.c +++ b/drivers/soundwire/cadence_master.c @@ -368,10 +368,10 @@ cdns_fill_msg_resp(struct sdw_cdns *cdns, if (!(cdns->response_buf[i] & CDNS_MCP_RESP_ACK)) { no_ack = 1; dev_dbg_ratelimited(cdns->dev, "Msg Ack not received\n"); - if (cdns->response_buf[i] & CDNS_MCP_RESP_NACK) { - nack = 1; - dev_err_ratelimited(cdns->dev, "Msg NACK received\n"); - } + } + if (cdns->response_buf[i] & CDNS_MCP_RESP_NACK) { + nack = 1; + dev_err_ratelimited(cdns->dev, "Msg NACK received\n"); } }