Dear all,
Does anyone know the difference between VideoPortGetDeviceBase and VideoPortMapMemory ?
These two functions are supported by VideoPort driver to map a bus-relative physical memory range into system virtual address space.
Thanks in advance.
Matt
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Matt Wu writes:
> Does anyone know the difference between VideoPortGetDeviceBase and
> VideoPortMapMemory ? These two functions are supported by
> VideoPort driver to map a bus-relative physical memory range into
> system virtual address space.
VideoPortGetDeviceMemory has no way of passing a process handle
therefore it can’t really be used to handle
IOCTL_VIDEO_SHARE_VIDEO_MEMORY. You must use VideoPortMapMemory for
this (where the process handle can be passed in using the
VirtualAddress parameter).
In general VideoPortMapMemory is used both here
(IOCTL_VIDEO_SHARE_VIDEO_MEMORY) and in IOCTL_VIDEO_MAP_VIDEO_MEMORY
even though I think VideoPortGetDeviceBase could be used in the
latter. VideoPortGetDeviceBase may be used in your HwVidFindAdapter
function to map any physical memory or IO ranges needed by the
miniport itself. This is the only place I have seen it used in
practice.
Gordon
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