Re: is overwriting user data acceptable

Hi Rik, Thanks for the information. I have coded it using uint32_t/ uint8_t data types. Should I consider it ok and should I change them to u32. Regards. Bhanu On Fri, Jul 4, 2008 at 6:14 PM, Rik van Riel [EMAIL PROTECTED] wrote: On Fri, 4 Jul 2008 17:38:25 -0700 bhanu nani [EMAIL PROTECTED

is overwriting user data acceptable

Hi Guys, I am working on a driver that I plan to submit to the Linux sources in the next few month on the PPC communication processor Architecture. That makes me little worried about the acceptance of this driver into the Linux tree. if I have an ioctl that passes me some data in a structure

Driver model to choose

Hi Guys, I have a Xilinx chip that is custom build. If this chip does nothing than a simple switching, LCD control, RTC and watch dog setup. What is driver model that I can you to write driver for this kind of a chip. I am planning to use Char. IO requirements may be there Please give me both

How to come a process slept after schedule() call.

Hi all, I am working on driver locking schemes provided in Linux. I am doing that with no device just to a handle memory buffer i.e. just like scull device. I am not able to get one way of sleeping to work. I am trying out as said in LLD3. Please find the code snippets of read/write method

Re: kernel preemption does not work

Hi Guys, I am not sure whether this API is avialable to user space but this code snippet is part of Kernel module. Test code: -- read() { if(down_interruptible()) return error; mdelay(1); up(); } With this code in place, I try to do

kernel preemption does not work

Hi all, I am trying to test kernel preemption in my driver. When I first compiled the Linux kernel and tested it, I found it to be non-preemptible. Later I realised that my kernel was build with premption disabled. I enabled kernel premption in processort section i.e. CONFIG_PREEMPT and rebuild

Re: Working of spinlock_irqsave

Hi Rajat, Thanks for your simple and clear explanation. If so, How? How is it different from irqsave call? It will work only if you are absolutely sure that interrupts will be enabled when this code gets executed. If you are not sure about the current state of interrupts when you are

Re: Reader/writer semaphores

and not read. If you use write semaphore, given 'a' as global variable it will be protected surely. Does that answer your question? Let me know if you need more explanation on this. Thanks - A On Thu, Apr 3, 2008 at 10:09 PM, bhanu nani [EMAIL PROTECTED] wrote: Hi Sahlot, First thing, I

Re: Reader/writer semaphores

-- Please let me know how is this code trying to handle concurency situation with cond_resched(); How is that going to help? This would be a great piece of information. Regards, Mukund Jampala On 4/4/08, bhanu nani [EMAIL

Re: Reader/writer semaphores

acquiring a read sem protects your data (which is updated in critical section). Does that answer your question? Let me know if you have more confusion on this. Thanks -A On Wed, Apr 2, 2008 at 11:52 PM, bhanu nani [EMAIL PROTECTED] wrote: Hi Fabio, My understanding: Semaphore are the tools

Re: Reader/writer semaphores

attributes. Is there no need to protect them? or some location updates to my own structure which I have to make for future use. - Bhanu On 4/1/08, Fabio De Francesco [EMAIL PROTECTED] wrote: On Tuesday 01 April 2008 23:57:47 bhanu nani wrote: Hi guys, I was studying on reader-writer

Reader/writer semaphores

Hi guys, I was studying on reader-writer semaphores in LLD3. Refered to some samaphore books. but some clarity is missing. Reader/Writer Semaphores: The critical section between down_read, up_read semaphores provides read-only access to the protected resources. I assume that any data in between

Re: Does the File suystem do buffer cache for char device

-0700, bhanu nani wrote: I have completed reading the LLD3 and The Design of Unix Operating Sysem. I have just started writing my own version of LLD example drivers. My machine runs on FC8. Theoritically, understand that the buffercache only avialable for Block driver not char devices

Does the File suystem do buffer cache for char device

Hi all, I have completed reading the LLD3 and The Design of Unix Operating Sysem. I have just started writing my own version of LLD example drivers. My machine runs on FC8. Theoritically, understand that the buffercache only avialable for Block driver not char devices. I wrote a scull type char

sudo configuration on FC8

Hi all, I am trying to configure a user without the prompting for a passwd on my FC-8 Linux. I added on the follwoing statement to /etc/sudoers with 'visudo' bhanuALL=(ALL) NOPASSWD:ALL With this in place, it is still asking for a passwd when I am trying to load a module. Can someone