Re: [RFC 4/4] drm: Add NVIDIA Tegra support
From: Alan Cox <hidden>
Date: 2012-04-11 14:52:37
Also in:
dri-devel, linux-iommu, linux-tegra
Maybe your question is answered by my reply to Alan's comment. The mapping is actually done to get a linear view for the display controller which doesn't support SG transfers. The kernel and user-space already have virtual linear buffers.
The framebuffer currently needs a physically contiguous map for the console devices. Well you could vmap them but that is pretty hideous on a 32bit platform with 32bit 1080p display plugged into it! Alan