This is a note to let you know that I've just added the patch titled
usb: dwc3: gadget: Queue PM runtime idle on disconnect event
to the 6.6-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:
usb-dwc3-gadget-queue-pm-runtime-idle-on-disconnect-event.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 3c7af52c7616c3aa6dacd2336ec748d4a65df8f4 Mon Sep 17 00:00:00 2001
From: Wesley Cheng <quic_wcheng@xxxxxxxxxxx>
Date: Wed, 3 Jan 2024 13:49:46 -0800
Subject: usb: dwc3: gadget: Queue PM runtime idle on disconnect event
From: Wesley Cheng <quic_wcheng@xxxxxxxxxxx>
commit 3c7af52c7616c3aa6dacd2336ec748d4a65df8f4 upstream.
There is a scenario where DWC3 runtime suspend is blocked due to the
dwc->connected flag still being true while PM usage_count is zero after
DWC3 giveback is completed and the USB gadget session is being terminated.
This leads to a case where nothing schedules a PM runtime idle for the
device.
The exact condition is seen with the following sequence:
1. USB bus reset is issued by the host
2. Shortly after, or concurrently, a USB PD DR SWAP request is received
(sink->source)
3. USB bus reset event handler runs and issues
dwc3_stop_active_transfers(), and pending transfer are stopped
4. DWC3 usage_count decremented to 0, and runtime idle occurs while
dwc->connected == true, returns -EBUSY
5. DWC3 disconnect event seen, dwc->connected set to false due to DR
swap handling
6. No runtime idle after this point
Address this by issuing an asynchronous PM runtime idle call after the
disconnect event is completed, as it modifies the dwc->connected flag,
which is what blocks the initial runtime idle.
Fixes: fc8bb91bc83e ("usb: dwc3: implement runtime PM")
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Wesley Cheng <quic_wcheng@xxxxxxxxxxx>
Link: https://lore.kernel.org/r/20240103214946.2596-1-quic_wcheng@xxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/dwc3/gadget.c | 7 +++++++
1 file changed, 7 insertions(+)
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -3983,6 +3983,13 @@ static void dwc3_gadget_disconnect_inter
usb_gadget_set_state(dwc->gadget, USB_STATE_NOTATTACHED);
dwc3_ep0_reset_state(dwc);
+
+ /*
+ * Request PM idle to address condition where usage count is
+ * already decremented to zero, but waiting for the disconnect
+ * interrupt to set dwc->connected to FALSE.
+ */
+ pm_request_idle(dwc->dev);
}
static void dwc3_gadget_reset_interrupt(struct dwc3 *dwc)
Patches currently in stable-queue which might be from quic_wcheng@xxxxxxxxxxx are
queue-6.6/usb-dwc3-gadget-queue-pm-runtime-idle-on-disconnect-event.patch
queue-6.6/usb-dwc3-gadget-handle-ep0-request-dequeuing-properly.patch
