Wonderful! Thank you Pete!! > -----Original Message----- > From: Pete Batard <p...@akeo.ie> > Sent: Wednesday, September 1, 2021 12:46 PM > To: devel@edk2.groups.io > Cc: ardb+tianoc...@kernel.org; l...@nuviainc.com; Samer El-Haj-Mahmoud > <samer.el-haj-mahm...@arm.com> > Subject: [edk2-platforms][PATCH 1/1] Platform/RaspberryPi/RPi4: Add _DSM > ACPI method for 32-bit MMIO xHCI access > > With the upcoming release of Windows 11, Microsoft has introduced a new > USB > Device-Specific Method (_DSM) function to enforce 64-bit xHCI registers to > be accessed through two sequential 32-bit requests. The new function > (Query > controller register access type - Function 6) is documented at: > https://docs.microsoft.com/en-us/windows-hardware/drivers/bringup/usb- > device-specific-method---dsm- > > Support for this feature is required on the raspberry Pi 4 where there is > a bug/limitation in the xHCI stack that prevents full range 64-bit access > from working correctly. It should be noted that an equivalent for this _DSM > is not required on Linux, as 64-bit xHCI register access is already broken > down into 2x32-bit by the drivers there. > > With this _DSM, and unlike what is the case for Windows 10, Windows 11 can > now be installed on the Raspberry Pi 4 without having to alter any of the > installation files, as we were able to validate using the latest Windows 11 > Build 22000 Insider image. > > Signed-off-by: Pete Batard <p...@akeo.ie> > Tested-by: Pete Batard <p...@akeo.ie> > --- > Platform/RaspberryPi/AcpiTables/Xhci.asl | 21 ++++++++++++++++++++ > 1 file changed, 21 insertions(+) > > diff --git a/Platform/RaspberryPi/AcpiTables/Xhci.asl > b/Platform/RaspberryPi/AcpiTables/Xhci.asl > index 9b37277956d9..00b0cd29c69c 100644 > --- a/Platform/RaspberryPi/AcpiTables/Xhci.asl > +++ b/Platform/RaspberryPi/AcpiTables/Xhci.asl > @@ -138,6 +138,27 @@ DefinitionBlock (__FILE__, "SSDT", 5, "RPIFDN", > "RPI4XHCI", 2) > Debug = "xHCI enable" > > Store (0x6, CMND) > > } > > + > > + /* > > + * Microsoft's USB Device-Specific Methods. See: > > + * https://docs.microsoft.com/en-us/windows- > hardware/drivers/bringup/usb-device-specific-method---dsm- > > + */ > > + Name (DSMU, ToUUID ("ce2ee385-00e6-48cb-9f05-2edb927c4899")) > > + > > + Method (_DSM, 4, Serialized) { > > + If (LEqual (Arg0, DSMU)) { // USB capabilities UUID > > + Switch (ToInteger (Arg2)) { > > + Case (0) { // Function 0: List of > supported functions > > + Return (Buffer () { 0x41 }) // 0x41 - Functions 0 > and 6 supported > > + } > > + Case (6) { // Function 6: > RegisterAccessType > > + Return (Buffer () { 0x01 }) // 0x01 - Must use 32bit > register > access > > + } > > + Default { } // Unsupported > > + } > > + } > > + return (Buffer () { 0x00 }) // Return 0x00 for > anything > unsupported > > + } > > } // end XHC0 > > } //end SCB0 > > } //end scope sb > > -- > 2.30.2.windows.1
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