The FPGA initiates DMA from its FIFO to the pre allocated RAM. So the DMA is
not a PC’s resource.
In this case, is there any meaning to the fields:
AutoInitialize, ScatterGather, DemandMode, DmaChannel, DmaPort, BusNumber ?
Upon interrupt I’m setting the FPGA to put next fragment in a specified
offet within this buffer, but for some reason the data always written to the
start of the buffer.
I’m sure the FPGA firmware is OK. Under an old XP driver written in WDM, all
works fine.
With all due respect, is there something specific in the documentation about the fields you mentioned that isn’t clear? The docs seem pretty clear to me, which is why I’m asking.
According to the documentation:
ScatterGather : Indicates whether the device supports scatter/gather DMA.
In my opinion, this is not clear enough.
The FPGA writes data to a physical RAM. It has no scatter gather capability.
So I’m asking if in this case this field has any meaning.
Z.V
-----Original Message-----
From: xxxxx@osr.com
Sent: Saturday, August 01, 2015 05:45 PM
To: Windows System Software Devs Interest List
Subject: RE:[ntdev] ScatterGather field in DEVICE_DESCRIPTION for
AllocateCommonBuffer
With all due respect, is there something specific in the documentation about
the fields you mentioned that isn’t clear? The docs seem pretty clear to
me, which is why I’m asking.
ScatterGather
For a bus-master DMA device, this member indicates whether the device
supports scatter/gather DMA. Set to TRUE if the device can do scatter/gather
DMA. Otherwise, set this member to FALSE.
That is pretty clear, your device does not use scatter gather set the field
to FALSE!
Peter was too polite to say it, but you really should consider taking a
class on Windows device drivers. The value of such a class is not only
learning the basics, but more important learning how to search for the
answers on your own.
-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Zvi Vered
Sent: Saturday, August 01, 2015 2:47 PM
To: Windows System Software Devs Interest List
Subject: Re: RE:[ntdev] ScatterGather field in DEVICE_DESCRIPTION for
AllocateCommonBuffer
Hi Peter,
According to the documentation:
ScatterGather : Indicates whether the device supports scatter/gather DMA.
In my opinion, this is not clear enough.
The FPGA writes data to a physical RAM. It has no scatter gather capability.
So I’m asking if in this case this field has any meaning.
Z.V
-----Original Message-----
From: xxxxx@osr.com
Sent: Saturday, August 01, 2015 05:45 PM
To: Windows System Software Devs Interest List
Subject: RE:[ntdev] ScatterGather field in DEVICE_DESCRIPTION for
AllocateCommonBuffer
With all due respect, is there something specific in the documentation about
the fields you mentioned that isn’t clear? The docs seem pretty clear to
me, which is why I’m asking.