From: Ilija Hadzic Date: Tue, 15 May 2012 20:40:10 +0000 (-0400) Subject: drm: track dev_mapping in more robust and flexible way X-Git-Tag: v3.6-rc1~83^2~8 X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=949c4a34afacfe800fc442afac117aba15284962;p=pandora-kernel.git drm: track dev_mapping in more robust and flexible way Setting dev_mapping (pointer to the address_space structure used for memory mappings) to the address_space of the first opener's inode and then failing if other openers come in through a different inode has a few restrictions that are eliminated by this patch. If we already have valid dev_mapping and we spot an opener with different i_node, we force its i_mapping pointer to the already established address_space structure (first opener's inode). This will make all mappings from drm device hang off the same address_space object. Some benefits (things that now work and didn't work before) of this patch are: * user space can mknod and use any number of device nodes and they will all work fine as long as the major device number is that of the drm module. * user space can even remove the first opener's device nodes and mknod the new one and the applications and windowing system will still work. * GPU drivers can safely assume that dev->dev_mapping is correct address_space and just blindly copy it into their (private) bdev.dev_mapping For reference, some discussion that lead to this patch can be found here: http://lists.freedesktop.org/archives/dri-devel/2012-April/022283.html Signed-off-by: Ilija Hadzic Signed-off-by: Dave Airlie --- Reading git-diff-tree failed