[tfaber] 74408: [USBEHCI][USBOHCI] - Touch the virtual address of DMA buffers before calling MmGetPhysicalAddress on them. This ensures page directories are correctly set up for the current process...

Author: tfaber
Date: Wed Apr 26 10:53:32 2017
New Revision: 74408

URL: http://svn.reactos.org/svn/reactos?rev=74408&view=rev
Log:
[USBEHCI][USBOHCI]
- Touch the virtual address of DMA buffers before calling MmGetPhysicalAddress on them.
This ensures page directories are correctly set up for the current process context, and
fixes random DMA operation failures ("MM:MmGetPhysicalAddressFailed"). This is
not a hack -- using MmGetPhysicalAddress for DMA in the first place is.
CORE-9224 #resolve

Modified:
    trunk/reactos/drivers/usb/usbehci/usb_request.cpp
    trunk/reactos/drivers/usb/usbohci/usb_request.cpp

Modified: trunk/reactos/drivers/usb/usbehci/usb_request.cpp
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/drivers/usb/usbehci/usb_re…
==============================================================================
--- trunk/reactos/drivers/usb/usbehci/usb_request.cpp	[iso-8859-1] (original)
+++ trunk/reactos/drivers/usb/usbehci/usb_request.cpp	[iso-8859-1] Wed Apr 26 10:53:32
2017
@@ -615,8 +615,9 @@
     do
     {
         //
-        // get address
-        //
+        // get address (HACK)
+        //
+        *(volatile char *)TransferBuffer;
         Address = MmGetPhysicalAddress(TransferBuffer);
 
         //

Modified: trunk/reactos/drivers/usb/usbohci/usb_request.cpp
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/drivers/usb/usbohci/usb_re…
==============================================================================
--- trunk/reactos/drivers/usb/usbohci/usb_request.cpp	[iso-8859-1] (original)
+++ trunk/reactos/drivers/usb/usbohci/usb_request.cpp	[iso-8859-1] Wed Apr 26 10:53:32
2017
@@ -784,8 +784,9 @@
         }
 
         //
-        // get physical page
-        //
+        // get physical page (HACK)
+        //
+        *(volatile char *)TransferBuffer;
         Page = MmGetPhysicalAddress(Buffer).LowPart;
 
         //