I've been searching around and can't find a solution for this. The official NVIDIA Tegra 2 Linux SDK (L4T) doesn't include both XRandR or the VideoMode X11 extension for querying available video modes. My next thought was to parse the log file for video modes. Of course most of the time it's at /var/log/Xorg.0.log but I'd rather not always make that assumption. The XF86misc extension provides a way to get the log path but that extension is also not installed by default.
So I'm wondering if anyone knows of any other way to figure out what video modes are available and also what the current video mode of the display is.
The core X protocol does not mention modes. You have to use extensions. There's nothing wrong with that, that's what extensions are for.
Also, remember that there's no guarantee that the machine you're displaying on is the same machine as you're running on, so parsing the X log file is destined to fail if your app ever runs across the network.
Related
I've implemented an OSXFUSE-based file system. It works fine on 10.8, but on Mavericks MS Word opens existing documents as blank (although I am, apparently, returning the correct data - I see the contents in the preview icon. Also, if I copy a file to a real hard drive and open it, it opens fine).
This issue is fixed on Mavericks if I mount my filesystem with the "local" flag. However, using this flag introduces other problems - e.g., it looks like it causes Finder to do some more aggressive caching, hence some file are not visible in Finder (although I can ls them in terminal).
Ideally I want to be able to mount the filesystem without this local flag (my implementation stores file on the network, so passing this flag looks wrong), but the problem with blank Word documents really puzzles me.
We have been able to track down the problem to - wait for it - Google Chrome. When Google Chrome is running while the volume is mounted, the problem appears. If Google Chrome is not running, Word/Excel/etc. files open just fine.
We've been in contact with Benjamin (OSXFUSE developer). Please also see his answer regarding this issue on the OSXFUSE mailing list:
https://groups.google.com/d/msg/osxfuse-group/URlw-n-Qakg/bLw2fHHDe7sJ
So far I have not found any bugs in osxfuse that might explain this behavior. The odd thing is that the files are not corrupted or empty. After copying the files to another volume they open just fine. Using LibreOffice to open the file on the FUSE volume works, too.
Chrome and Office seem to be based on the Carbon framework (which is deprecated since Mountain Lion). I believe the issue is somehow related to Carbon since non-Carbon apps do not seem to be affected. Every time a volume is mounted Chrome queries the volume’s capabilities and attributes (and maybe more). As far as I can tell all these file system operations return successful without any errors. But from this point on Office will fail to open documents.
In my opinion the two most likely reasons for this are:
osxfuse might break the VFS file system contract on Mavericks. I’ve been looking into this for some time now but I have not found any clues supporting this.
There might be a bug in the Carbon/CarbonCore framework. The odd thing is that there are no issues when using the stock network file systems afp or smb.
The two possible "fixes" (or rather "workarounds") for this issue seem to be (for now):
Use the "local" mount option (which might introduce other problems and is generally not recommend to use)
Do not use the "volname" mount option. The problem seems only to occur when the "volname" mount option is used. If no custom volume name is set, the problem seems not to occur and Excel/Word/etc. files open just fine - regardless whether Google Chrome was running at mount time.
I've seen the same and likewise local is not an option. Similar problems with Photoshop.
Some findings from my implementation
The problem doesn't occur on first run after reboots.
The problem begins occurring after program exit.
I solved this problem by manually dismounting (and waiting a few seconds) before exiting my program. If unmount is successful, on next run the mount again performs fine.
If the program ever terminates or dismounting fails (file in use, etc) then the volume's read-access is borked in Word/Photoshop on next mount.
Rebooting resolves issue.
Does this match what you're seeing?
Windows lets you develop a filter driver to catch file I/O's on VFS. But I can't seem to find something similar for Mac. It does have something called Filter Schemes, but those are for HFS+. Anyone know if there is a way for me to intercept file I/O's on Mac without using programs like MacFUSE?
I found out that Mac OS X does not allow filter drivers at all.
“A stacking file system (sometimes called a filter file system) sits on top of another file system and modifies its behavior in some way. The canonical example of a stacking file system is an encryption file system. You could stack this file system on top of any existing file system to provide encryption support. Apple does not support the development of stacking VFS plug-ins on Mac OS X” (http://developer.apple.com/mac/library/qa/qa2001/qa1242.html)
kauth (introduced in OS X 10.4) is the closest thing to FS filter drivers.
Here is a nice write-up on the various APIs present on Mac OS X. It should be a good starting point.
Link
I'm not at all familier with the Windows technologies that you mention, but it sounds like you might be looking for FSEvents.
http://developer.apple.com/mac/library/documentation/Darwin/Conceptual/FSEvents_ProgGuide/Introduction/Introduction.html
The file system events API provides a
way for your application to ask for
notification when the contents of a
directory hierarchy are modified. For
example, your application can use this
to quickly detect when the user
modifies a file within a project
bundle using another application.
It also provides a lightweight way to
determine whether the contents of a
directory hierarchy have changed since
your application last examined them.
For example, a backup application can
use this to determine what files have
changed since a given time stamp or a
given event ID.
You should read this document if your
application works with a large number
of files—particularly if your
application works with large
hierarchies of files.
Is there a version of the CUPS server available for Windows? Looking at the CUPS source code it seems it is ready for Visual Studio compilation, but I did not find any trace of an actual supported package. I'd like to set up a CUPS server on Windows so that I can print form Linux/MacOSX/Win clients to printers I set up on this server.
I've got a new answer for you:
Since some time there is a project called ippsample on GitHub. It's slowly approaching a mature version 1.0 release.
Here are the first two sentences of given as self-description in the mandatory README file:
"This code provides sample implementations of IPP Clients, Printers, and Proxies. It is largely based upon the CUPS software, with substantial changes to the ippproxy and ippserver implementations to make them more general-purpose and configurable." (my emphasis)
This project is hosted by the ISTO Printer Working Group (PWG), the same industry organization which develops and promotes the IPP as a general standard.
The ippserver, ipptool, ippfind, ippproxy and ipptransform components of the IPP Sample project together make up for a standard-conforming IPP Everywhere implementation, covering the client as well as the server side of printing.
The GitHub code for IPP Sample project is maintained by the very same Mike Sweet who also develops CUPS -- so it's the real thing.
Yes, it compiles and works nicely on Windows, and there are a bunch of .vclxproj and .sln files available to make the build process with MS Visual Studio as smooth as possible.
Yes, the IPP Sample code is working and can print to a CUPS server (or receive print jobs from there) running on macOS or any blend of Linux.
No, this is not yet a fully-blown CUPS server for Windows which can serve as a drop-in replacement for a Windows print server. It does not have with ALL the features which would be required.
But if you want to create such a beast:
this is the place were you would have to poke around first;
this is were you possibly could fork the code and start adding functionality to get where you want to go.
Oh, and did you know that Apple recently changed the license conditions for CUPS and made it more permissive, moving away from GPL2 to Apache 2.0 licensing?
You have never heard of "IPP Everywhere" before? It is the future of "driverless" printing.
Never heard of "driverless printing"? A slightly modified (and stripped down) version of it already implemented as "Apple AirPrint" for iPhone and iPad devices.
The current implementation of the CUPS-based printing stack includes new pieces of code in the cups-drivers project which recently moved to GitHub. This new code implements IPP Everywhere functionality.
This cups-filters project is under the stewardship by The Linux Foundation's OpenPrinting department ever since Apple handed over these parts of the original CUPS source code to them when they became no longer useful for macOS but were still important to Linux.
What are the basic ideas of driverless printing then?
Have the devices automatically announce their presence and their type of service in the local network. Use the IETF standard protocols mDNS and DNS-SD (which are implemented in macOS under the name of "Bonjour" and in Linux as "Avahi") to take note of the offered services.
Tell the print clients that they can use the IPP protocol in order to get a query response when they make a get-printer-attributes request. This request will tell them which set of print options the devices support. The print clients can then show an exactly tailored print dialog to show to the printing user a selection of choices. The print client will also be told what job submission formats each devices supports. This MUST be either PDF or a simple raster format called "PWG-Raster".
So... where would you need a specific "printer driver" in such an environment? Everything and everyone can create PDF documents nowadays. Check! No need for a device-specific conversion to any other print language.
Are there printers which support IPP Everywhere already? Oh yes, look here -- they are all said to be fully compliant with the standard:
List of IPP Everywhere printer models
The .sln and .vcproj files you've been seeing in the CUPS sources are not meant to compile all of CUPS for Windows.
They serve to compile only a few of its utilities (such as ipptool.exe)...
Making the complete CUPS server+filtering code work on Windows would be a daunting task, since Windows spooling and printing is so much different from the Unix world.
CUPS uses Internet Printing Protocol for client-server communications. According to Technet article, Windows can be used as IPP host:
To enable a computer running Windows
Server 2008 to act as a server
supporting Internet printing, you must
install the Web Server (IIS) role, the
Print Services role, and the Internet
Printing role service in the Print
Services role.
Moreover, it seems that Windows, Linux and Mac OS X clients can use printers shared via SMB.
"Making the complete CUPS server+filtering code work on Windows would be a daunting task, since Windows spooling and printing is so much different from the Unix world."
Back in the dial up internet days, I ran into a problem where some IPS' had a replacement dll for modem functionality. The problem with it was that the dll prevented legit programs from accessing the modem until you uninstalled the IPS program.
This same technique can be used to create a Windows CUPS server by writing a Windows spooling and printing replacement program that, rather than printing directly to the printer, hands off the printing tasks to the CUPS server.
It would of course, take someone with in depth knowledge of the windows spooling and printing protocols.
cygwin ports has patch files for implementing a cups in (some versions of) cygwin. I can't speak to how well it might work.
https://github.com/cygwinports-extras/cups
I have been looking into the possibility of creating a soft copy(image/EMF file) of everything printed from Windows - for archival purposes. Does anyone know if it is possible to create a hooking DLL that can grab the printed data in such a general way?
A low tech way of solving it might be to install pdf printer driver as the default printer and remove all others and set it up to automatically write all the files to certain directory on the network and then write a tiny app on another computer to monitor that folder for changes and if any new pdfs appear just print them out to a real printer.
Edit: Otherwise there's apparently something called the Print Monitor API. Here's an article that describes using that from VC++ 6 and seems to be pretty much what you want (assuming it's still supported by the OS you use).
Having looked at this problem in more detail the best solution seems to handle it through Spooler notifications in the Win32.
Windows XP Embedded is missing the NULL or "NUL" device. For one thing, Visual Studio seems to require it and trying to build a project aborts with a PRJ0015 error.
Anyone know how to configure an XPe image to include support for the NUL device?
"Null Device Driver" is available in the XPe Target Designer, but it's normally hidden. Apparently each component has a visibility level, and if it's lower than that set in the Target Designer options (Tools->Options), it's hidden. Null Device Driver is at level 200, so I set the level to 100 and could see it and install it.
There's another important situation where you're going to want the NUL device: if you're installing some or all of the Cygwin UNIX solutions for Windows. In particular, if you're doing something like, oh, I don't know, to pick a completely random example, trying to put an SSH server on the damned thing so you can, just on a lark, say, log in and maintain it.
That's right-- Cygwin actually maps its UNIX /dev/null device to the Windows NUL device. You know, for maximum compatibility. Just in case the platform-specific implementation of IMMEDIATELY THROWING DATA INTO THE TOILET AND OBLITERATING IT, NEVER TO BE SEEN AGAIN, UNTIL THE HEAT DEATH OF THE UNIVERSE, happened to be novel and innovative.
While cygwin will INSTALL without NUL available, it will not, in fact, actually enjoy a typical work day. This is most evident the first time you try to launch a bash shell, and notice a slew of error messages about /dev/null resulting in no such file or directory errors. One presumes the device is perhaps actually just an NTFS link, but who knows.
In any case, the fix is to add the "Null Device Driver" component, helpfully located under Software -> System -> Other, a surprisingly small category which also contains such useful components as Internet Checkers, the Schedule Service Command Line Utility, the 1394 Kernel Debugger Support Library, EBCDIC support for Microsoft Bob, some cheat codes for Zork, and the code pages to say "(A)bort, (R)etry, (I)gnore, (F)ail?" in Muppet Swedish ("(B)ork, b(o)rk, bo(r)k, bor(k)?")
Hope this helps,
Matt "Breakpoint" Heck
Running Visual Studio itself on XP Embedded doesn't seem like it'd be supported. You should build on a full OS and then just deploy your application to XP embedded.