Tagged Questions

6
votes
8answers
2k views

how to code drivers?

I want to code drivers in C in linux os, though I think its very tough. Can I get some hints as to how to start or books to follow? Drivers can be from my USB port to graphics card!! I know as to ...
3
votes
3answers
171 views

What's the point of a Linux character device driver if you can just use outb/inb from userspace? [closed]

I'm having a hard time understand when I should write a device driver instead of just sending opcodes directly to the hardware via outb from my userspace programs. I initially figured that I should ...
3
votes
1answer
3k views

Linux driver access through sysfs

I'm making a small kernel module to provide user-space access to some kernel-mode only features of an ARMv7 chip (specifically, cache control). I'm reading through Linux Device Drivers by Corbet, ...
3
votes
1answer
672 views

learning linux drivers

I am learning now days programming drivers. I am doing my learning from this book Linux Device Drivers But I am little bit lack of practice. Can you recommend me some simple projects that I can get ...
3
votes
1answer
346 views

Linux kernel struct file pointer

Is it guaranteed that a struct file pointer won't be deallocated and reallocated somewhere else in memory during its open to close lifecycle? I want to uniquely identify file structs that are passed ...
2
votes
2answers
650 views

Are ioctl driver functions executed from an atomic context under linux 2.6?

I am tracking down a "scheduling while atomic" error in one of our drivers, and am wondering if ioctl's are an atomic context. Also if any one has anything to share on how to get into and out of ...
2
votes
1answer
755 views

Linux USB driver probe() problem

I'm currently work on kernel-mode USB driver for Seowon SWU-3220A WiMAX USB modem. It is a complex device (after plugging it appear in system as USB CDROM, and driver needs to switch it to modem ...
2
votes
2answers
443 views

The same driver for multiple network cards — performance bottleneck?

I'm using driver e1000e for multiple Intel network cards (Intel EXPI9402PT, based on 82571EB chip). The problem is that when I'm trying to utilize maximum speed (1GB) on more than one interface, speed ...
2
votes
2answers
747 views

Embedded Linux Read and Write Video from a USB port

I've got an embedded Linux project where I need to read video in through a USB port, make some modifications to that video (such as compression), and then send it back to the host via preferably the ...
2
votes
2answers
267 views

Use SATA HDD as Block Device

I'm totally new to the Linux Kernel, so I probably mix things up. But any advice will help me ;) I have a SATA HDD connected via a PCIe SATA Card and I try to use read and write like on a block ...
2
votes
0answers
728 views

Writing USB driver for Raspberry Pi [closed]

I am trying to write a USB device driver for Raspberry Pi board (practising on my Ubuntu desktop first). Whenever two flash drives are inserted, data from second will automatically be copied into the ...
1
vote
1answer
69 views

Is there a Linux driver for testing transport protocols?

I am trying to test some communication protocols, both commercial and homegrown. I would like to find an Ethernet driver that allows me to degrade the channel in a controllable fashion. For instance ...
1
vote
1answer
441 views

How to make a Windows ADB driver as simple as the existing Linux ADB driver?

For some reason on Windows you need a different driver for every device to work with ADB. In Linux you just add the ID's to a file. We have been trying to figure out how to make a more universal ADB ...
1
vote
2answers
305 views

Call a userspace function from within a Linux kernel module

I'm programming a simple Linux character device driver to output data to a piece of hardware via I/O ports. I have a function which performs floating point operations to calculate the correct output ...
1
vote
1answer
455 views

Linux How to test a PCIe driver?

I wrote a simple PCIe driver and I want to test if it works. For example, If it is possible to write and read to the memory which is used from the device as well. How can I do that? And which stuff ...

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