[linux-dvb] problems in em28xx-video.c

kevin liu lwtbenben at gmail.com
Wed Sep 19 07:54:51 CEST 2007


Dear Markus:
    In em28xx-video.c, when you design memory map function,
    You used this state:
++++++++
for(i=0; i<dev->num_frames; i++){
    if(dev->frame[i].buf.m.offset >> PAGE_SHIFT == vma->pgoff)
        break;
}
++++++++
Why dev->frame[i].buf.m.off>>PAGE_SHIFT == vma->pgoff;
I see the mmap function implemented in Linux device driver3, it is like this:
if(remap_pfn_range(vma, vma_start, vm->vm_pgoff, vma_size, vma->vm_page_prot))
     return -EAGAIN;
......
......

And where did the frame[i].buf come from?
Could you please give me some explanation?



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