On Tue, Jun 02, 2015 at 06:39:48PM +0530, Vinod Koul wrote: > > > Do we have a real world example where we would want to DMA without a kernel > > > client, IOW a usermode client? > > > > memset/memcpy on large buffers ? > > > > And like I mentionned on the memset reintroduction serie, we do have a > > platform where we exactly want to do framebuffer-related operations > > (blitting for example, but also memset on the framebuffer itself) > > which usually are accelerated by the GPU, but that platform doesn't > > have any GPU while it has a DMA controller able to do just that. > > So you dont have a framebuffer driver which can invoke dmaengine ops? We do, but that would require adding possibly controversial ioctls, without covering the general use case (ie. offloading the copying and/or setting of arbitrarily large buffers from userspace). Maxime -- Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com
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