I have a USB printer device. I want to send file data to the USB printer from Linux. I am using libUsb for my code. I am getting timeout (libusb return value -7) always while sending. But I can able to send data in Windows for the same printer. What went wrong ? It seems ehci or uhci is not sending data to the printer. Please Help .
OS : Ubuntu 12.04 (32 Bit)
The below is my code snippet.
dev_handle = libusb_open_device_with_vid_pid(ctx, PRINTER_VID, PRINTER_PID);
if (dev_handle == NULL)
{
cout << "Cannot open device" << endl;
libusb_free_device_list(devs, 1); //free the list, unref the devices in it
return;
}
else
{
cout << "Device Opened" << endl;
}
if (libusb_kernel_driver_active(dev_handle, 0) == 1) //find out if kernel driver is attached
{
cout << "Kernel Driver Active" << endl;
if (libusb_detach_kernel_driver(dev_handle, 0) == 0) //detach it
cout << "Kernel Driver Detached!" << endl;
}
r = libusb_claim_interface(dev_handle, 0);
if (r < 0)
{
cout << "Cannot Claim Interface" << endl;
return 1;
}
cout << "Claimed Interface" << endl;
cout << "Writing Data..." << endl;
memset(data_buffer,0,64);
while(fgets((char *)data_buffer,64,fp))
{
errno = 0;
r = libusb_bulk_transfer(dev_handle,0x081 | LIBUSB_ENDPOINT_OUT, data_buffer, 64,&actual, 10);
cout<<"The return value of r is "<<r<< "::::" << actual << endl ;
memset(data_buffer,0,64);
}
The output is
The return value of r is -7::::0
The return value of r is -7::::0
Try to execute following comamnd from superuser and then reconnect device.
echo 0 > /sys/bus/usb/drivers_autoprobe
It helped me with some devices.
Related
I'm trying to run a parallel for loop with triSYCL. This is my code:
#define TRISYCL_OPENCL
#define OMP_NUM_THREADS 8
#define BOOST_COMPUTE_USE_CPP11
//standart libraries
#include <iostream>
#include <functional>
//deps
#include "CL/sycl.hpp"
struct Color
{
float r, g, b, a;
friend std::ostream& operator<<(std::ostream& os, const Color& c)
{
os << "(" << c.r << ", " << c.g << ", " << c.b << ", " << c.a << ")";
return os;
}
};
struct Vertex
{
float x, y;
Color color;
friend std::ostream& operator<<(std::ostream& os, const Vertex& v)
{
os << "x: " << v.x << ", y: " << v.y << ", color: " << v.color;
return os;
}
};
template<typename T>
T mapNumber(T x, T a, T b, T c, T d)
{
return (x - a) / (b - a) * (d - c) + c;
}
int windowWidth = 640;
int windowHeight = 720;
int main()
{
auto exception_handler = [](cl::sycl::exception_list exceptions) {
for (std::exception_ptr const& e : exceptions)
{
try
{
std::rethrow_exception(e);
} catch (cl::sycl::exception const& e)
{
std::cout << "Caught asynchronous SYCL exception: " << e.what() << std::endl;
}
}
};
cl::sycl::default_selector defaultSelector;
cl::sycl::context context(defaultSelector, exception_handler);
cl::sycl::queue queue(context, defaultSelector, exception_handler);
auto* pixelColors = new Color[windowWidth * windowHeight];
{
cl::sycl::buffer<Color, 2> color_buffer(pixelColors, cl::sycl::range < 2 > {(unsigned long) windowWidth,
(unsigned long) windowHeight});
cl::sycl::buffer<int, 1> b_windowWidth(&windowWidth, cl::sycl::range < 1 > {1});
cl::sycl::buffer<int, 1> b_windowHeight(&windowHeight, cl::sycl::range < 1 > {1});
queue.submit([&](cl::sycl::handler& cgh) {
auto color_buffer_acc = color_buffer.get_access<cl::sycl::access::mode::write>(cgh);
auto width_buffer_acc = b_windowWidth.get_access<cl::sycl::access::mode::read>(cgh);
auto height_buffer_acc = b_windowHeight.get_access<cl::sycl::access::mode::read>(cgh);
cgh.parallel_for<class init_pixelColors>(
cl::sycl::range<2>((unsigned long) width_buffer_acc[0], (unsigned long) height_buffer_acc[0]),
[=](cl::sycl::id<2> index) {
color_buffer_acc[index[0]][index[1]] = {
mapNumber<float>(index[0], 0.f, width_buffer_acc[0], 0.f, 1.f),
mapNumber<float>(index[1], 0.f, height_buffer_acc[0], 0.f, 1.f),
0.f,
1.f};
});
});
std::cout << "cl::sycl::queue check - selected device: "
<< queue.get_device().get_info<cl::sycl::info::device::name>() << std::endl;
}//here the error appears
delete[] pixelColors;
return 0;
}
I'm building it with this CMakeLists.txt file:
cmake_minimum_required(VERSION 3.16.2)
project(acMandelbrotSet_stackoverflow)
set(CMAKE_CXX_STANDARD 17)
set(SRC_FILES
path/to/main.cpp
)
find_package(OpenCL REQUIRED)
set(Boost_INCLUDE_DIR path/to/boost)
include_directories(${Boost_INCLUDE_DIR})
include_directories(path/to/SYCL/include)
set(LIBS PRIVATE ${Boost_LIBRARIES} OpenCL::OpenCL)
add_executable(${PROJECT_NAME} ${SRC_FILES})
set_target_properties(${PROJECT_NAME} PROPERTIES DEBUG_POSTFIX _d)
target_link_libraries(${PROJECT_NAME} ${LIBS})
When I try to run it, I get this message: libc++abi.dylib: terminating with uncaught exception of type trisycl::non_cl_error from path/to/SYCL/include/triSYCL/command_group/detail/task.hpp line: 278 function: trisycl::detail::task::get_kernel, the message was: "Cannot use an OpenCL kernel in this context".
I've tried to create a lambda of mapNumber in the kernel but that didn't make any difference. I've also tried to use this before the end of the scope to catch errors:
try
{
queue.wait_and_throw();
} catch (cl::sycl::exception const& e)
{
std::cout << "Caught synchronous SYCL exception: " << e.what() << std::endl;
}
but nothing was printed to the console except the error from before. And I've also tried to make an event of the queue.submit call and then call event.wait() before the end of the scope but again the exact same output.
Does any body have an idea what else I could try?
The problem is that triSYCL is a research project looking deeper at some aspects of SYCL while not providing a global generic SYCL support for an end-user. I have just clarified this on the README of the project. :-(
Probably the problem here is that the OpenCL SPIR kernel has not been generated.
So you need to first compile the specific (old) Clang & LLVM from triSYCL https://github.com/triSYCL/triSYCL/blob/master/doc/architecture.rst#trisycl-architecture-for-accelerator. But unfortunately there is no simple Clang driver to use all the specific Clang & LLVM to generate the kernels from the SYCL source. Right know it is done with some ad-hoc awful Makefiles (look around https://github.com/triSYCL/triSYCL/blob/master/tests/Makefile#L360) and, even if you can survive to this, you might encounter some bugs...
The good news is now there are several other implementations of SYCL which are quite easier to use, quite more complete and quite less buggy! :-) Look at ComputeCpp, DPC++ and hipSYCL for example.
Am trying to open the web camera through GSTREAMER API using Opencv on windows, but am getting
this error at runtime
GStreamer-CRITICAL **: gst_element_get_state: assertion 'GST_IS_ELEMENT (element)' failed
OpenCV | GStreamer warning: GStreamer: unable to query pipeline state
Below is code am running
VideoCapture capture(0,CAP_GSTREAMER);
if (capture.isOpened()) {
std::cout << "Camera 0 via " << capture.getBackendName() << " backend" << std::endl;
std::cout << "Frame width: " << capture.get(CAP_PROP_FRAME_WIDTH) << std::endl;
std::cout << " height: " << capture.get(CAP_PROP_FRAME_HEIGHT) << std::endl;
std::cout << "Capturing FPS: " << capture.get(CAP_PROP_FPS) << std::endl;
}
However camera is working fine with Gstreamer command
gst-launch-1.0.exe -v ksvideosrc device-index=0 ! autovideosink
I have built OpenCV4.0 with GStreamer enabled, what exactly missing element here and is there a fix for this?
Try the below code:
const char* pipeline= "ksvideosrc device-index=0 ! autovideoconvert ! appsink";
int cap_id = CAP_GSTREAMER;
VideoCapture cap( pipeline, cap_id);
how do I use getline to separate a string ex. "you8only8live8once"? This solution only sets my first word to "you" and then stops at the first "8".
Also if I want to the "8" to be an arbitrary delimiter do I just put in cin >> delimiter; then change "getline(cin, phrase, '8');" to "getline(cin, phrase, delimiter);"?
istringstream inSS;
string phrase;
string firstWord;
string secondWord;
string thirdWord;
string fourthWord;
cout << "Please enter a digit infused string to explode:" << endl;
cout << "Please enter the digit delimiter:" << endl;
getline(cin, phrase, '8');
inSS.str(phrase);
inSS >> firstWord >> secondWord >> thirdWord >> fourthWord;
cout << "The 1st word is: " << firstWord << endl;
cout << "The 2nd word is: " << secondWord << endl;
cout << "The 3rd word is: " << thirdWord << endl;
cout << "The 4th word is: " << fourthWord << endl;
return 0;
SSE intrinsics includes _mm_shuffle_ps xmm1 xmm2 immx which allows one to pick 2 elements from xmm1 concatenated with 2 elements from xmm2. However this is for floats, (implied by the _ps , packed single). However if you cast your packed integers __m128i, then you can use _mm_shuffle_ps as well:
#include <iostream>
#include <immintrin.h>
#include <sstream>
using namespace std;
template <typename T>
std::string __m128i_toString(const __m128i var) {
std::stringstream sstr;
const T* values = (const T*) &var;
if (sizeof(T) == 1) {
for (unsigned int i = 0; i < sizeof(__m128i); i++) {
sstr << (int) values[i] << " ";
}
} else {
for (unsigned int i = 0; i < sizeof(__m128i) / sizeof(T); i++) {
sstr << values[i] << " ";
}
}
return sstr.str();
}
int main(){
cout << "Starting SSE test" << endl;
cout << "integer shuffle" << endl;
int A[] = {1, -2147483648, 3, 5};
int B[] = {4, 6, 7, 8};
__m128i pC;
__m128i* pA = (__m128i*) A;
__m128i* pB = (__m128i*) B;
*pA = (__m128i)_mm_shuffle_ps((__m128)*pA, (__m128)*pB, _MM_SHUFFLE(3, 2, 1 ,0));
pC = _mm_add_epi32(*pA,*pB);
cout << "A[0] = " << A[0] << endl;
cout << "A[1] = " << A[1] << endl;
cout << "A[2] = " << A[2] << endl;
cout << "A[3] = " << A[3] << endl;
cout << "B[0] = " << B[0] << endl;
cout << "B[1] = " << B[1] << endl;
cout << "B[2] = " << B[2] << endl;
cout << "B[3] = " << B[3] << endl;
cout << "pA = " << __m128i_toString<int>(*pA) << endl;
cout << "pC = " << __m128i_toString<int>(pC) << endl;
}
Snippet of relevant corresponding assembly (mac osx, macports gcc 4.8, -march=native on an ivybridge CPU):
vshufps $228, 16(%rsp), %xmm1, %xmm0
vpaddd 16(%rsp), %xmm0, %xmm2
vmovdqa %xmm0, 32(%rsp)
vmovaps %xmm0, (%rsp)
vmovdqa %xmm2, 16(%rsp)
call __ZStlsISt11char_traitsIcEERSt13basic_ostreamIcT_ES5_PKc
....
Thus it seemingly works fine on integers, which I expected as the registers are agnostic to types, however there must be a reason why the docs say that this instruction is only for floats. Does someone know any downsides, or implications I have missed?
There is no equivalent to _mm_shuffle_ps for integers. To achieve the same effect in this case you can do
SSE2
*pA = _mm_shuffle_epi32(_mm_unpacklo_epi32(*pA, _mm_shuffle_epi32(*pB, 0xe)),0xd8);
SSE4.1
*pA = _mm_blend_epi16(*pA, *pB, 0xf0);
or change to the floating point domain like this
*pA = _mm_castps_si128(
_mm_shuffle_ps(_mm_castsi128_ps(*pA),
_mm_castsi128_ps(*pB), _MM_SHUFFLE(3, 2, 1 ,0)));
But changing domains may incur bypass latency delays on some CPUs. Keep in mind that according to Agner
The bypass delay is important in long dependency chains where latency is a bottleneck, but
not where it is throughput rather than latency that matters.
You have to test your code and see which method above is more efficient.
Fortunately, on most Intel/AMD CPUs, there is usually no penalty for using shufps between most integer-vector instructions. Agner says:
For example, I found no delay when mixing PADDD and SHUFPS [on Sandybridge].
Nehalem does have 2 bypass-delay latency to/from SHUFPS, but even then a single SHUFPS is often still faster than multiple other instructions. Extra instructions have latency, too, as well as costing throughput.
The reverse (integer shuffles between FP math instructions) is not as safe:
In Agner Fog's microarchitecture on page 112 in Example 8.3a, he shows that using PSHUFD (_mm_shuffle_epi32) instead of SHUFPS (_mm_shuffle_ps) when in the floating point domain causes a bypass delay of four clock cycles. In Example 8.3b he uses SHUFPS to remove the delay (which works in his example).
On Nehalem there are actually five domains. Nahalem seems to be the most effected (the bypass delays did not exist before Nahalem). On Sandy Bridge the delays are less significant. This is even more true on Haswell. In fact on Haswell Agner said he found no delays between SHUFPS or PSHUFD (see page 140).
I'm writing an iOS app that uses CoreAudio's Audio Unit API, and at a certain point I do a AudioUnitGetProperty(audioUnit, kAudioUnitProperty_StreamFormat, ...) call. At that point I set a breakpoint to look into the ASBD, and I find the mFormatFlags field is 41. The question is, can I decode the actual flag names from that number (such as kAudioFormatFlagIsNonInterleaved | kAudioFormatFlagIsPacked | ...)?
Thanks a lot.
Here is an ostream overload for printing an ASBD, taken mostly from Apple sample code:
std::ostream& operator<<(std::ostream& out, const AudioStreamBasicDescription& format)
{
unsigned char formatID [5];
*(UInt32 *)formatID = OSSwapHostToBigInt32(format.mFormatID);
formatID[4] = '\0';
// General description
out << format.mChannelsPerFrame << " ch, " << format.mSampleRate << " Hz, '" << formatID << "' (0x" << std::hex << std::setw(8) << std::setfill('0') << format.mFormatFlags << std::dec << ") ";
if(kAudioFormatLinearPCM == format.mFormatID) {
// Bit depth
UInt32 fractionalBits = ((0x3f << 7)/*kLinearPCMFormatFlagsSampleFractionMask*/ & format.mFormatFlags) >> 7/*kLinearPCMFormatFlagsSampleFractionShift*/;
if(0 < fractionalBits)
out << (format.mBitsPerChannel - fractionalBits) << "." << fractionalBits;
else
out << format.mBitsPerChannel;
out << "-bit";
// Endianness
bool isInterleaved = !(kAudioFormatFlagIsNonInterleaved & format.mFormatFlags);
UInt32 interleavedChannelCount = (isInterleaved ? format.mChannelsPerFrame : 1);
UInt32 sampleSize = (0 < format.mBytesPerFrame && 0 < interleavedChannelCount ? format.mBytesPerFrame / interleavedChannelCount : 0);
if(1 < sampleSize)
out << ((kLinearPCMFormatFlagIsBigEndian & format.mFormatFlags) ? " big-endian" : " little-endian");
// Sign
bool isInteger = !(kLinearPCMFormatFlagIsFloat & format.mFormatFlags);
if(isInteger)
out << ((kLinearPCMFormatFlagIsSignedInteger & format.mFormatFlags) ? " signed" : " unsigned");
// Integer or floating
out << (isInteger ? " integer" : " float");
// Packedness
if(0 < sampleSize && ((sampleSize << 3) != format.mBitsPerChannel))
out << ((kLinearPCMFormatFlagIsPacked & format.mFormatFlags) ? ", packed in " : ", unpacked in ") << sampleSize << " bytes";
// Alignment
if((0 < sampleSize && ((sampleSize << 3) != format.mBitsPerChannel)) || (0 != (format.mBitsPerChannel & 7)))
out << ((kLinearPCMFormatFlagIsAlignedHigh & format.mFormatFlags) ? " high-aligned" : " low-aligned");
if(!isInterleaved)
out << ", deinterleaved";
}
else if(kAudioFormatAppleLossless == format.mFormatID) {
UInt32 sourceBitDepth = 0;
switch(format.mFormatFlags) {
case kAppleLosslessFormatFlag_16BitSourceData: sourceBitDepth = 16; break;
case kAppleLosslessFormatFlag_20BitSourceData: sourceBitDepth = 20; break;
case kAppleLosslessFormatFlag_24BitSourceData: sourceBitDepth = 24; break;
case kAppleLosslessFormatFlag_32BitSourceData: sourceBitDepth = 32; break;
}
if(0 != sourceBitDepth)
out << "from " << sourceBitDepth << "-bit source, ";
else
out << "from UNKNOWN source bit depth, ";
out << format.mFramesPerPacket << " frames/packet";
}
else
out << format.mBitsPerChannel << " bits/channel, " << format.mBytesPerPacket << " bytes/packet, " << format.mFramesPerPacket << " frames/packet, " << format.mBytesPerFrame << " bytes/frame";
return out;
}