On Tue, Jan 16, 2018 at 04:35:59PM -0800, Gurchetan Singh wrote: > This is required to use buffers allocated by vgem on AMD and ARM devices. > We're experiencing a case where eviction of the cache races with userspace > writes. To fix this, flush the cache after retrieving a page. > > Signed-off-by: Gurchetan Singh <gurchetansingh@xxxxxxxxxxxx> > --- > drivers/gpu/drm/vgem/vgem_drv.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/gpu/drm/vgem/vgem_drv.c b/drivers/gpu/drm/vgem/vgem_drv.c > index 35bfdfb746a7..fb263969f02d 100644 > --- a/drivers/gpu/drm/vgem/vgem_drv.c > +++ b/drivers/gpu/drm/vgem/vgem_drv.c > @@ -112,6 +112,7 @@ static int vgem_gem_fault(struct vm_fault *vmf) > break; > } > > + drm_flush_pages(obj->base.dev->dev, &page, 1); Uh ... what exactly are you doing? Asking because the entire "who's responsible for coherency" story is entirely undefined still when doing buffer sharing :-/ What is clear is that currently vgem entirely ignores this (there's not begin/end_cpu_access callback), mostly because the shared dma-buf support in drm_prime.c also entirely ignores this. And doing a one-time only flushing in your fault handler is definitely not going to fix this (at least not if you do anything else than one-shot uploads). -Daniel > } > return ret; > } > -- > 2.13.5 > > _______________________________________________ > dri-devel mailing list > dri-devel@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/dri-devel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
