Branch: refs/heads/master
Home: https://github.com/tianocore/edk2
Commit: 2ba169b02f7eebb34816c2d02a1cd9f92a524b1a
https://github.com/tianocore/edk2/commit/2ba169b02f7eebb34816c2d02a1cd9f92a524b1a
Author: Marlboro_Chuang <[email protected]>
Date: 2026-09-21 (Mon, 21 Sep 2026)
Changed paths:
M MdeModulePkg/Bus/Usb/UsbBusDxe/UsbUtility.c
Log Message:
-----------
MdeModulePkg/UsbBusDxe: Raise TPL to CALLBACK for wanted UsbIo connect
Raise TPL to TPL_CALLBACK around the ConnectController() call in
UsbBusRecursivelyConnectWantedUsbIo() and restore the original TPL
afterward.
UsbBusRecursivelyConnectWantedUsbIo() is normally reached through the
DriverBinding Start routine invoked by gBS->ConnectController(), which
runs at TPL_APPLICATION. While the wanted UsbIo handle is being
connected, the USB device can be removed. The device removal polling
event in UsbBus runs at TPL_CALLBACK. If the connect runs at
TPL_APPLICATION, that event can preempt the connection and cause
commands to be sent to a stale or non-existent USB device address,
producing a lot of timeout transfers.
This differs from UsbConnectDriver(), which is called from the
enumeration polling event (XHCI async event) and is usually already
at TPL_CALLBACK or TPL_NOTIFY. That function uses RestoreTPL()/
RaiseTPL() to ensure ConnectController() runs at TPL_CALLBACK.
Signed-off-by: Marlboro_Chuang <[email protected]>
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