From 3a6c5c5ab734dbe27bd4dede6def79c24154d049 Mon Sep 17 00:00:00 2001 From: Mathias Nyman Date: Thu, 25 Aug 2022 18:08:39 +0300 Subject: [PATCH] xhci: Add grace period after xHC start to prevent premature runtime suspend. commit 33e321586e37b642ad10594b9ef25a613555cd08 upstream. After xHC controller is started, either in probe or resume, it can take a while before any of the connected usb devices are visible to the roothub due to link training. It's possible xhci driver loads, sees no acivity and suspends the host before the USB device is visible. In one testcase with a hotplugged xHC controller the host finally detected the connected USB device and generated a wake 500ms after host initial start. If hosts didn't suspend the device duringe training it probablty wouldn't take up to 500ms to detect it, but looking at specs reveal USB3 link training has a couple long timeout values, such as 120ms RxDetectQuietTimeout, and 360ms PollingLFPSTimeout. So Add a 500ms grace period that keeps polling the roothub for 500ms after start, preventing runtime suspend until USB devices are detected. Cc: stable@vger.kernel.org Signed-off-by: Mathias Nyman Link: https://lore.kernel.org/r/20220825150840.132216-3-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/xhci-hub.c | 11 +++++++++++ drivers/usb/host/xhci.c | 4 +++- drivers/usb/host/xhci.h | 2 +- 3 files changed, 15 insertions(+), 2 deletions(-) diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c index f65f1ba2b5929..b9754784161d7 100644 --- a/drivers/usb/host/xhci-hub.c +++ b/drivers/usb/host/xhci-hub.c @@ -1647,6 +1647,17 @@ int xhci_hub_status_data(struct usb_hcd *hcd, char *buf) status = bus_state->resuming_ports; + /* + * SS devices are only visible to roothub after link training completes. + * Keep polling roothubs for a grace period after xHC start + */ + if (xhci->run_graceperiod) { + if (time_before(jiffies, xhci->run_graceperiod)) + status = 1; + else + xhci->run_graceperiod = 0; + } + mask = PORT_CSC | PORT_PEC | PORT_OCC | PORT_PLC | PORT_WRC | PORT_CEC; /* For each port, did anything change? If so, set that bit in buf. */ diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index e3767651c9a9e..3cac7e40456eb 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -148,9 +148,11 @@ int xhci_start(struct xhci_hcd *xhci) xhci_err(xhci, "Host took too long to start, " "waited %u microseconds.\n", XHCI_MAX_HALT_USEC); - if (!ret) + if (!ret) { /* clear state flags. Including dying, halted or removing */ xhci->xhc_state = 0; + xhci->run_graceperiod = jiffies + msecs_to_jiffies(500); + } return ret; } diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h index 81e1bfdf83988..10a4230d95c37 100644 --- a/drivers/usb/host/xhci.h +++ b/drivers/usb/host/xhci.h @@ -1830,7 +1830,7 @@ struct xhci_hcd { /* Host controller watchdog timer structures */ unsigned int xhc_state; - + unsigned long run_graceperiod; u32 command; struct s3_save s3; /* Host controller is dying - not responding to commands. "I'm not dead yet!"