On Thu, 15 Nov 2012 16:53:58 +0100, Daniel Vetter <daniel.vetter at ffwll.ch> wrote: > Since we drop dev->struct_mutex when going through the slowpath, the > object might have been moved out of the cpu domain. Hence we need to > clflush the entire object to ensure that after the ioctl returns, > everything is coherent again (interwoven writes are ill-defined > anyway). > > But we only need to do this if we start in the cpu domain and the > object requires flushing for coherency. So don't do the flushing if > the object is coherent anyway or if we've done in-line clfushing > already. > > v2: i915_gem_clflush_object already checks whether the object is > coherent and if so, drops the flushing. Hence we don't need to check > that ourselves, simplifying the condition. > > v3: Reorder the checks for better clarify (and adjust the comment > accordingly), suggested by Chris Wilson. > > Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch> Yup, the comment makes much more sense now. Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk> -Chris -- Chris Wilson, Intel Open Source Technology Centre
