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It is an operation that is not interruptible. So, a single machine code read or write.
Why is it important? SO that if you are reading a chunk of memory bigger that this you make sure you don't get interrupted.
In the Linux kernel, the term 'atomic' (for which there is a func, in_atomic()) means 'is the code running at a privileged level' which is either at soft or hard interrupt level.
Thus timer expiry is soft interrupt. A card triggering an interrupt is hard.
So in the windows kernel DPC or DIRQL are the 'atomic' modes. Passive, is non atomic.
Harolds answer is spot on, just wanted to add a bit more colour.
One other feature of running 'in atomic', ie, at soft or hard interrupt, is you cant access paged out memory or functions. Else you get a page fault exception.
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I am trying to access rtsp url using QuickTime player. Now if there is some authentication set, then it asks for it otherwise it just plays the stream. It is good till here. But if I add username and password in the url, then it shows message: Server Not Found. I am passing the url in the following manner.
rtsp://username:password@IP-Address:Port
How could I pass rtsp url in QuickTime player with the credentials?. Thanks for any input
This world is going to explode due to international politics, SOON.
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Sharath C V wrote: Mobile Broadband
Is that the same as 'wireless WAN' ?
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I cant see any mention up updates to it on that link.
I actually worked with Microsoft on the development of this API starting off on Vista. It didn't make the cut for that OS but came in on Win7.
Its complex. All that home network, roaming network, signal strength, PIN entry etc. I hope they haven't made it worse! 
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Thanks very much for your reply Matt.
And great to know that you worked on WWAN APIs!
No, the APIs are nice. It is pretty nice as to how they have pulled it off. Finding it really helpful. Since Microsoft did that homework, our live is better and we can spend quality time on other work items.
-Sharath
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Hi all:
I am new one in wdf. I got a problem.
I write a usb hid touch driver in xp(send one touch as mouse).
My problem is, when the usb touch device is reset(the reset command are not
sent by host), How can I send the reset command from usb touch device to host
and notify Os get descriptor again and re addressing?
My English is not good, please forgive me.
best regard, Victor
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My friend recently formatted his pc (only C drive) and re-installed XP. Now he faces a weird problem. The usb ports are working fine but it's not reading any pen drives other than his own. At first I found it hard to beleive but that's what is happening. His pen drive works fine but none of the others do. Any help?
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Open the device manager, go to Disk Management and lok for the drives (see also http://support.microsoft.com/kb/309000[^]). They might just lack a drive letter.
Otherwise, look in device manager for "unknown devices".
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Only XP Service Pack 2 has built-in support for USB drives. Tell your friend to install Service Pack 2, and the drives will work.
The difficult we do right away...
...the impossible takes slightly longer.
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What a pain in the but it is for getting a driver signed.
Why is it so dependent on hardware? If the hardware hasn't got a serial number, fail. Device descriptor is a bit shoddy at times, fail. Device goes unresponsive. BSOD and fail.
Not only that its also dependent on the PC its tested on. One of them has a failure as big as the titanic iceberg right in the ACPI/BIOS subsystem.
So the Windows kernel is a highly structured and layered environment, and the driver you are testing sits on at least two others, and is a long way from the hardware, so why does the HCK fail on hardware errors? Why doesn't it implement a virtual piece of hardware via a filter, which it has anyway, and test JUST your driver?
It really is a pain in the but at times. Especially if the hardware is a bit flaky.
"The whole idea that carbon dioxide is the main cause of the recent global warming is based on a guess that was proved false by empirical evidence during the 1990s." climate-models-go-cold
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I have a HP Pavilion Elite with dual monitors. I'd like to add a third monitor. Does this require a new video card or some other hardware?
If it's not broken, fix it until it is
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Never done this myself... but you can probably find video cards that support it. When you purchase a new video card however, make sure it supports three simultaneous video outputs (just having three outputs doesn't guarantee that it's support it). I have a desktop that has three outputs (two DVI and one HDMI) but you can only use two of them at a time. Not sure if this is a hardware limitation or just the driver software. Either way, make sure it's supported by the video card.
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Hello. AFAIK, you can stream h264 live video from IP camera on windows media player. But when I enter URL (rtsp://xxx.xxx.xxx.xxx:7070), following message is shown
Windows Media Player can not play the file because the specified protocol is not supported.
Now the same url works fine on VLC player but NOT on windows media plyer. I have read the following knowledge base article but could not fix the issue. What could be wrong? Thanks for any pointer.
modified 14-Apr-14 2:23am.
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I read most of them but could not find the solution. Most of them are repetition of the KB article I provided the link of. Just not sure what should I try now.
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Why doesn't the Bluetooth for android allow hands free talk and text like the windows does?
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Why don't you ask Google?
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It does... I have a Nexus phone and you can certainly do hands-free calling.
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I have a Samsung Galaxy S4, it allows hands-free calling and text, and my previous phone, the Samsung Stratosphere v2 also did, not that I used it much since it had a keyboard. Just takes a little setup.
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Does anyone remember Tetradyne DriverX windows driver software for WinXP and prior? I am looking for a copy of the file DxIntr3.h to build the kernel. I have all other sources. I bought a source license but Tetradyne Software is gone now. Much appreciation.
More information:
I started out just hoping someone had a copy of the file. W/o a copy I see I need to reinvent the missing file.
I have gotten it to compile with the definitions:
typedef struct
{
ULONG nOffset;
ULONG cb;
} READ_WRITE_DMA_BUFFER_INPUT, *PREAD_WRITE_DMA_BUFFER_INPUT;
typedef unsigned char *PUCHAR;
The whole function that requires these definitions is extracted from the file DxDriver.c:
NTSTATUS DxReadWriteDmaBuffer(PDXDEV_EXTENSION pExtension, PVOID pIoBuffer,
ULONG cbInput, PMDL mdl, BOOLEAN read)
{
PREAD_WRITE_DMA_BUFFER_INPUT params;
PUCHAR pOutBuffer;
// Validate parameters
if (!pIoBuffer || (cbInput < sizeof(READ_WRITE_DMA_BUFFER_INPUT)))
return STATUS_INVALID_PARAMETER;
params = (PREAD_WRITE_DMA_BUFFER_INPUT) pIoBuffer;
if ((params->nOffset + params->cb) > pExtension->nDmaBufSize)
return STATUS_INVALID_PARAMETER;
if (!mdl || (MmGetMdlByteCount(mdl) < params->cb))
return STATUS_INVALID_PARAMETER;
if (!pExtension->pDmaBuffer)
return STATUS_UNSUCCESSFUL;
pOutBuffer = MmGetSystemAddressForMdl(mdl);
if (!pOutBuffer)
return STATUS_UNSUCCESSFUL;
if (read)
{
RtlCopyMemory(
pOutBuffer,
(PUCHAR) pExtension->pDmaBuffer + params->nOffset,
params->cb);
}
else
{
RtlCopyMemory(
(PUCHAR) pExtension->pDmaBuffer + params->nOffset,
pOutBuffer,
params->cb);
}
return STATUS_SUCCESS;
}
Anyone see any problem here?
Thanks for the help and clues. Now I move to debug. Bless you all.
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Thanks Mr. Muchies for clues and hints. I have it actually working now. Turned out the DMA part was crucial. Now the trick is to port to Windows 7. Any advice or good links you have? Seems like eliminating the HAL calls will be a large part.
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
modified 9-Apr-14 14:59pm.
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Blimey, never heard of it, and I have been writing windows drivers since the 90s.
Can you recreate it? Sounds like it might have some defines, some wrappers round WDM api funcs, that kind if thing.
"The whole idea that carbon dioxide is the main cause of the recent global warming is based on a guess that was proved false by empirical evidence during the 1990s." climate-models-go-cold
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To build a version 4xxx kernel driver they use some stuff defined for the version 3xxx driver. Most is interrupt related and since the user mode part of the driver compiles just fine w/o it I concluded that I did not need the old interrupt parts so I faked it.
However the DMA parts wrap new methods around the methods of the prior versions and therefore need some definitions for the driver to compile. At the moment I need definition/declarations for PREAD_WRITE_DMA_BUFFER_INPUT and PUCHAR. These might be structures based on compile errors I get when I typedef'd them to integers to see what would happen.
I was hoping in the vastness of space and time and the Internet someone had a copy of the file DxIntr3.h that they would share.
Thanks for caring.
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I guess the second one is unsigned char * (Pointer to Unsigned CHAR). The first one may be the same or more likely a pointer to the second (unsigned char ** as pointer to address of DMA input buffer).
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