Re: kernel driver access application memory

Hi, On Wed, Jan 15, 2014 at 11:45 PM, m silverstri <michael.j.silverstri@gmail.com> wrote:

Hi,

If my application allocate memory for input and output buffers, and pass the pointer to a kernel driver (via v4l2 queue buffer operation), can the kernel driver access it? Do I need to setup DMA before teh kernel driver can read/write to it?

If your application is allocating memory for v4l2 buffers how are you making sure its contiguous ? What call are you using to allocate memory @application level ? If the application is allocating buffers its USER_PTR buffer. Yes kernel can access the buffer. For reading and writing of buffers you dont need to setup DMA. Regards, --Prabhakar Lad http://in.linkedin.com/in/prabhakarlad