On Fri, Nov 15, 2019 at 10:37 AM Gerd Hoffmann <kraxel@xxxxxxxxxx> wrote: > > > You need memory pressure, to force ttm to unmap the bo, not userspace. So > > roughly > > 1. create bo > > 2. mmap it through drm fd, write some stuff > > 3. export to dma-buf, mmap it, verify stuff is there > > 4. create a pile more bo, mmap them write to them > > 5. once you've thrashed all of vram enough, recheck your original bo. If > > I'm right you should get the following: > > - drm fd mmap still show right content > > - dma-buf fd mmap shows random crap that you've written into other > > buffers > > > > Ofc you need to make sure that an mmap actually forces the buffer into > > vram. So might need a combo of modeset+mmap, to make that happen. Plain > > mmap might just give you ptes that point into system memory, which is not > > managed by ttm like vram. > > Is any move buffer good enough to trigger this, i.e. will SYSTEM -> VRAM > work too? That'll be easier because all I need to do is map the buffer > to a crtc to force pinning to vram, then check if the mappings are > intact still ... I think that should work too. Just make sure you actually write through SYSTEM first (maybe with some printk or whatever). -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
