vramfs is designed to take the memory range and directly turn it into a usable filesystem. The structures are not actually in VRAM, but the file contents are. Vramfs has a builtin mechanism as described to avoid conflicting with the region in use by the framebuffer console. I don't really know about the mtd device, but I thought it would be good kernel coding practice to write a filesystem driver to pull off a stunt like that. I also wrote this in consideration of the GPU which probably wouldn't know how to handle the fragmentation that would inevitably happen if ext3 needed to write blocks in a non-contiguous manner, this fs enforces the rule that files are always unbroken with only a start and length. Also, doesn't mtd come in as a block device? So you'd have to format the memory region using a filesystem like ext3, right? And as a block device you can't use mmap() to map that region directly into your process space, right? > Jonathan Campbell wrote: >> >> So far I've tested it against 2.6.25.17 and 2.6.28 on both x86 and >> x86_64 with reads, writes, directory creation, symlink creation, and >> mmap() and it seems to work fine. >> Just give it a range of memory on the bus, or the >> domain:bus:device:function numbers of a VGA PCI device, and it will >> mount the VGA video RAM and allow files to exist there. >> As a special hack: you can also specify the size of the active >> framebuffer console so that fbcon doesn't collide with this driver >> (unless you want to see what your files look like splattered across >> your screen, ha). The active VRAM area becomes a "sentinel" file >> named "framebuffer". >> >> What do you guys think? >> > > How is this different from the MTD driver we already have? > > -hpa > -- > To unsubscribe from this list: send the line "unsubscribe > linux-kernel" in > the body of a message to majordomo at vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > >
