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Questions tagged [irq]

An interrupt request is a hardware signal sent to the processor that temporarily stops a running program and allows to handle a hardware event.

In an IBM PC compatible personal computer, an interrupt request (or IRQ) is a hardware signal sent to the processor that temporarily stops a running program and allows a special program, an interrupt handler, to run instead. Interrupts are used to handle such events as data receipt from a modem or network, or a key press or mouse movement. The interrupt request level (IRQL) is the priority of an interrupt request.

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how to set all system irq for first 4 cores

server: i have servers with 2 intel 10 cores cpus or 8 cores. So some has 40 cores, some has 32 cores (enable intel HT) background: i am running our application, which will isolate cpus, currently, i isolate the last 32 cores (core 8-39) for that…
yixuan
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IRQ numbers in Output of lspci

For one of my pci device, output of lspci -vvv says pin A routed to 19. but output of lspci -b -vvv gives 255. All the pci devices gives irq 255 in lspci -b -vvv, while for lspci -vvv it gives different numbers. Can anyone please explain this?
Savan
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How to measure latency between hardware interrupt and related system call?

I have a Linux machine with two PCIe RS-485 cards (XR17V354 & XR17V352). I have one port on one of the cards hardwired to one port on the other card. These cards are driven by the generic serial driver (serial8250). I am running a test and measuring…
bsirang
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High bandwidth Networking and the Windows "System Interrupts" Process

I am writing a massive UDP network application. Running traffic at 10gigabits per second. I have a very high "System Interrupts" CPU usage in task manager. Reading about what this means, I see: What Is the “System Interrupts” Process? System…
eshalev
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Higher priority task failed to preempt current task after ISR done in 2.6.34 with RT patch

The arch is powerpc. I changed the ISR from threaded to no-threaded. The ISR wake-up another FIFO task with prio==19 Sometimes at the end of 'ret_from_except' when do 'resume_kernel', the preempt schedule condition is not fulfilled: the…
Qingchuan
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linux irq affinity set cannot take effctive

when i set irq for my Ethernet cannot be effective. (irq from 99-119) $ sudo cat /proc/irq/109/smp_affinity 00,00000400 $ sudo sh -c "echo 0 > /proc/irq/109/smp_affinity" $ sudo cat /proc/irq/109/smp_affinity 00,00000400 i want to set all ethernet…
yixuan
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Linux PCIe driver has periodic long latency for MSI

I have created a PCIe driver for Linux v4.1.15 (non PREEMPT_RT) with a single IRQ which is generated from an MSI from an FPGA. My ISR is: static irq_handler int_handler(int irq, void* dev_id, struct pt_regs* regs) { spin_lock(&my_lock); …
user2205930
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PID in case of irq context

what does "current->pid" prints in below 2 case 1) Hard IRQ context 2) Soft IRQ context I know IRQ context and process context are different, and PID must be invalid in case of IRQ context. But when try to print "current->pid" in IRQ context it is…
Gopinath
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Enable and Distribute IRQs in Linux

I am using imx6 sabrelite board in which Linux OS runs on core0 and RTOS on core1. I have configured GIC interrupt registers in RTOS but Linux OS overwrites it. I need to enable IRQs 88,142,143,150 and distribute it to core 1(RTOS) in linux source…
saravanan k
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Modified USB Keyboard Driver Not Receiving Key Presses (Linux)

I am trying to write a modified/custom USB keyboard driver. I'm having an issue with the irq handler not receiving key presses as expect. What I've done: Made a copy of /linux/driver/hid/usbhid/usbkbd.c link and modified usb_kbd_id_table to have…
MikeRawding
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Interrupts under Windows 7 do not trigger the function

I have some source code with a driver called TVicHW32 and under Windows XP it works fine and the interrupt handler gets called every time there is an interrupt from the ISA bus card. The ISA bus IRQ on 5 is set as reserved in the BIOS. If I run the…
Dave McLaughlin
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IRQ Handler Triple Fault

Currently my IRQ is triple faulting and giving the division by 0 error. Here is the viedo i recorded that will so show you this in action. irq.c++: #include "irq.h" #define PIC_MASTER_CONTROL 0x20 #define PIC_MASTER_MASK 0x21 #define…
amanuel2
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Adding Interrupt service routine in kernel

I am trying to add a switch/GPIO interrupt. I want to write it as part of kernel source tree. After building the kernel image and deploying to my custom board it has to appear in proc/interrupts. I have already written the module and it is working…
seereddi sekhar
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__irq and __irq_XXXX keywords in ARM programming

According to the ARM manual, __irq is a keyword defining the interrupt handlers in C code. However, I am not clear what would do keywords like: __irq_arm __irq_arm_ramfunc __irq_XXXX ..... HOWEVER, after reviewing the original of the code, it…
Lu Galhner
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Arduino CC3000 with pin 2

I'm having problem with the library Adafruit_CC3000 when using the IRQ on pin 2. If I change to 3, everything works fine, but I need the pin 3 free to use on a IR emission using the library IRremote. I'm using a CC3000 board on top of a Arduino…
Bateramos
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