On Thu, Sep 30, 2021 at 11:42:17AM +0200, Pawel Laszczak wrote:

From: Pawel Laszczak <pawell@cadence.com>

commit b69ec50b3e55c4b2a85c8bc46763eaf33060584 upstream

For DEV_VER_V3 version there exist race condition between clearing
ep_sts.EP_STS_TRBERR and setting ep_cmd.EP_CMD_DRDY bit.
Setting EP_CMD_DRDY will be ignored by controller when
EP_STS_TRBERR is set. So, between these two instructions we have
a small time gap in which the EP_STS_TRBERR can be set. In such case
the transfer will not start after setting doorbell.

Fixes: 7733f6c32e36 ("usb: cdns3: Add Cadence USB3 DRD Driver")
cc: <redacted> # 5.4.x
Tested-by: Aswath Govindraju <redacted>
Reviewed-by: Aswath Govindraju <redacted>
Signed-off-by: Pawel Laszczak <pawell@cadence.com>
---
 drivers/usb/cdns3/gadget.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

What kernel(s) are you wanting this applied to?

thanks,

greg k-h