Quoting Matthew Auld (2020-03-31 16:07:21)
On Tue, 31 Mar 2020 at 13:42, Chris Wilson chris@chris-wilson.co.uk wrote:
When we allocate space in the GGTT we may have to allocate a larger region than will be populated by the object to accommodate fencing. Make sure that this space beyond the end of the buffer points safely into scratch space, in case the HW tries to access it anyway (e.g. fenced access to the last tile row).
Reported-by: Imre Deak imre.deak@intel.com References: https://gitlab.freedesktop.org/drm/intel/-/issues/1554 Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Cc: Matthew Auld matthew.auld@intel.com Cc: Imre Deak imre.deak@intel.com Cc: stable@vger.kernel.org
Do we not need similar treatment for gen6? It seems to also play tricks with the nop clear range, or did we disable gen7 ppgtt in the end?
Currently disabled. But yes, if we use nop_clear_range we will need similar clearing. As this method turned out to be much easier than expected, I guess we should just do it anyway. -Chris