Hello, I'm trying to make framebuffer to work on PPC460EX board (canyonlands). The peculiarity of this platform is the fact that it has sizeof(unsigned long) = 4, but physical address on it is 36 bits width. It is a common to various pieces of the code to expect that unsigned long variable is able to contain physical address. Most of those places are easy to fix. The problem I'm stuck with is a fb_mmap() code. To find a right memory to map it uses information from struct fb_fix_screeninfo provided by the driver. This structure uses two unsigned long fields to hold physical addresses (smem_start and mmio_start). It would be easy to change that structure to use phys_addr_t instead of unsigned long, but this structure is a part of userspace ABI. It is returned to userspace on FBIOGET_FSCREENINFO ioctl. And now I'm stuck with it. In my driver code I have just overwritten the fb_mmap function with driver-private fb_mmap callback supporting 64-bit addressing, but this doesn't look like a generic and correct solution. What is the best way to fix this problem? Should we break ABI with the goal of correctness? Should we add new FBIOGET_FSCREENINFO2, which will return a correct structure with phys_addr_t (or simply u64) fields and make FBIOGET_FSCREENINFO a wrapper returning partially bogus structure (with smem_start and mmio_start fields being truncated to just unsigned long)? What would developers recommend? Thank you. -- With best wishes Dmitry -- With best wishes Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
