usb: dwc3: Avoid waking up gadget during startxfer
authorPrashanth K <quic_prashk@quicinc.com>
Wed, 28 Aug 2024 06:43:02 +0000 (12:13 +0530)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Tue, 3 Sep 2024 08:03:06 +0000 (10:03 +0200)
commit00dcf2fa449f23a263343d7fe051741bdde65d0b
tree45069781f210e60743663afb43e4e1d6d0b4f1b2
parent431c1646e1f86b949fa3685efc50b660a364c2b6
usb: dwc3: Avoid waking up gadget during startxfer

When operating in High-Speed, it is observed that DSTS[USBLNKST] doesn't
update link state immediately after receiving the wakeup interrupt. Since
wakeup event handler calls the resume callbacks, there is a chance that
function drivers can perform an ep queue, which in turn tries to perform
remote wakeup from send_gadget_ep_cmd(STARTXFER). This happens because
DSTS[[21:18] wasn't updated to U0 yet, it's observed that the latency of
DSTS can be in order of milli-seconds. Hence avoid calling gadget_wakeup
during startxfer to prevent unnecessarily issuing remote wakeup to host.

Fixes: c36d8e947a56 ("usb: dwc3: gadget: put link to U0 before Start Transfer")
Cc: stable@vger.kernel.org
Suggested-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Signed-off-by: Prashanth K <quic_prashk@quicinc.com>
Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/20240828064302.3796315-1-quic_prashk@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/usb/dwc3/gadget.c