From: Henry Lin <henryl@nvidia.com>
To: <mathias.nyman@linux.intel.com>
Cc: Henry Lin <henryl@nvidia.com>,
Mathias Nyman <mathias.nyman@intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
<linux-usb@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: [PATCH v3] xhci: fix runtime PM imbalance in USB2 resume
Date: Wed, 2 Mar 2022 14:51:06 +0800 [thread overview]
Message-ID: <20220302065106.85021-1-henryl@nvidia.com> (raw)
In-Reply-To: <2e5f4998-71bc-1fd5-8a82-b7392e4f7615@linux.intel.com>
A race between system resume and device-initiated resume may result in
runtime PM imbalance on USB2 root hub. If a device-initiated resume
starts and system resume xhci_bus_resume() directs U0 before hub driver
sees the resuming device in RESUME state, device-initiated resume will
not be finished in xhci_handle_usb2_port_link_resume(). In this case,
usb_hcd_end_port_resume() call is missing.
This changes calls usb_hcd_end_port_resume() if resuming device reaches
U0 to keep runtime PM balance.
Fixes: a231ec41e6f6 ("xhci: refactor U0 link state handling in get_port_status")
Signed-off-by: Henry Lin <henryl@nvidia.com>
---
Changes in v2:
- Add Fixes tag in change log
Changes in v3:
- Revise changelog
- Only call usb_hcd_end_port_resume() if xhci_irq() detected the device-initiated resume
[v2] https://lore.kernel.org/all/20220225071506.22012-1-henryl@nvidia.com/
[v1] https://lore.kernel.org/all/20220225055311.92447-1-henryl@nvidia.com/
drivers/usb/host/xhci-hub.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
index df3522dab31b..5e7a4dfc59d2 100644
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -1088,6 +1088,9 @@ static void xhci_get_usb2_port_status(struct xhci_port *port, u32 *status,
if (link_state == XDEV_U2)
*status |= USB_PORT_STAT_L1;
if (link_state == XDEV_U0) {
+ if (bus_state->resume_done[portnum])
+ usb_hcd_end_port_resume(&port->rhub->hcd->self,
+ portnum);
bus_state->resume_done[portnum] = 0;
clear_bit(portnum, &bus_state->resuming_ports);
if (bus_state->suspended_ports & (1 << portnum)) {
--
2.17.1
next prev parent reply other threads:[~2022-03-02 6:51 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-25 5:53 [PATCH] xhci: fix runtime PM imbalance in USB2 resume Henry Lin
2022-02-25 6:23 ` Greg Kroah-Hartman
2022-02-25 6:40 ` Henry Lin
2022-02-25 6:49 ` Greg Kroah-Hartman
2022-02-25 7:02 ` Henry Lin
2022-02-25 7:15 ` [PATCH v2] " Henry Lin
2022-02-25 9:16 ` Greg KH
2022-02-26 16:06 ` Henry Lin
2022-02-26 16:20 ` Henry Lin
2022-02-28 10:56 ` Mathias Nyman
2022-03-01 10:28 ` Henry Lin
2022-03-01 15:49 ` Mathias Nyman
2022-03-01 19:18 ` Henry Lin
2022-03-02 6:51 ` Henry Lin [this message]
2022-03-02 9:16 ` [PATCH v3] " Mathias Nyman
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