Gabor Kerenyi <wom@xxxxxxxxxxx> writes: > I'm trying to access the captured picture in the IRQ handler > (bttv_irq_switch_field) using the mmapped method. You can't. The buffer isn't mapped into the kernel address space. > I thought the capture->vb.dma.vmalloc should point to the > picture but it's NULL. using vmalloc is one of two ways to use capture buffers. The other one (which is used in the mmap case) is anonymous userspace memory. There is a scatter list which points to the pages used for the video buffer. But that doesn't help you. IIRC it isn't allowed call kmap() in IRQ context, so you can't access the actual data. Doing image processing in a IRQ handler is a bad idea anyway. What you are trying to do? And why to you think it is useful to do that in the IRQ handler? > The capture->bottom.dma is not NULL but I can't access > it when dereferencing the pointer. capture->top/bottom points to the risc instructions for the bt848 DMA controller. Gerd -- Weil die späten Diskussionen nicht mal mehr den Rotwein lohnen. -- Wacholder in “Melanie”
