From: Jim Lin jilin@nvidia.com
When a USB device is connected to the OTG port, the tegra_xhci_id_work() routine transitions the PHY to host mode and calls xhci_hub_control() with the SetPortFeature command to enable port power.
In certain cases, the XHCI controller may be in a low-power state when this operation occurs. If xhci_hub_control() is invoked while the controller is suspended, the PORTSC register may return 0xFFFFFFFF, indicating a read failure. This causes xhci_hc_died() to be triggered, leading to host controller shutdown.
Example backtrace: [ 105.445736] Workqueue: events tegra_xhci_id_work [ 105.445747] dump_backtrace+0x0/0x1e8 [ 105.445759] xhci_hc_died.part.48+0x40/0x270 [ 105.445769] tegra_xhci_set_port_power+0xc0/0x240 [ 105.445774] tegra_xhci_id_work+0x130/0x240
To prevent this, ensure the controller is fully resumed before interacting with hardware registers by calling pm_runtime_get_sync() prior to the host mode transition and xhci_hub_control().
Fixes: f836e7843036 ("usb: xhci-tegra: Add OTG support") Cc: stable@vger.kernel.org Signed-off-by: Jim Lin jilin@nvidia.com Signed-off-by: Wayne Chang waynec@nvidia.com --- drivers/usb/host/xhci-tegra.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/usb/host/xhci-tegra.c b/drivers/usb/host/xhci-tegra.c index 22dc86fb5254..70ec36e4ff5f 100644 --- a/drivers/usb/host/xhci-tegra.c +++ b/drivers/usb/host/xhci-tegra.c @@ -1364,6 +1364,7 @@ static void tegra_xhci_id_work(struct work_struct *work) tegra->otg_usb3_port = tegra_xusb_padctl_get_usb3_companion(tegra->padctl, tegra->otg_usb2_port);
+ pm_runtime_get_sync(tegra->dev); if (tegra->host_mode) { /* switch to host mode */ if (tegra->otg_usb3_port >= 0) { @@ -1393,6 +1394,7 @@ static void tegra_xhci_id_work(struct work_struct *work) }
tegra_xhci_set_port_power(tegra, true, true); + pm_runtime_mark_last_busy(tegra->dev);
} else { if (tegra->otg_usb3_port >= 0) @@ -1400,6 +1402,7 @@ static void tegra_xhci_id_work(struct work_struct *work)
tegra_xhci_set_port_power(tegra, true, false); } + pm_runtime_put_autosuspend(tegra->dev); }
#if IS_ENABLED(CONFIG_PM) || IS_ENABLED(CONFIG_PM_SLEEP)