From: Kenneth Graunke Date: Sat, 1 Jul 2017 08:55:52 +0000 (-0700) Subject: i965: Assert that we don't use CPU write maps to non-coherent buffers. X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=7250cbafb90271579a1d07160498e902996cbc97;p=mesa.git i965: Assert that we don't use CPU write maps to non-coherent buffers. Using CPU maps of non-coherent buffers can get us in a lot of trouble, and WC maps are a reasonable alternative anyway. Guard against shooting ourselves in the foot by adding an assert, and comment. Reviewed-by: Chris Wilson Reviewed-by: Matt Turner --- diff --git a/src/mesa/drivers/dri/i965/brw_bufmgr.c b/src/mesa/drivers/dri/i965/brw_bufmgr.c index d9b37bfae34..11251f15edc 100644 --- a/src/mesa/drivers/dri/i965/brw_bufmgr.c +++ b/src/mesa/drivers/dri/i965/brw_bufmgr.c @@ -669,6 +669,12 @@ brw_bo_map_cpu(struct brw_context *brw, struct brw_bo *bo, unsigned flags) { struct brw_bufmgr *bufmgr = bo->bufmgr; + /* We disallow CPU maps for writing to non-coherent buffers, as the + * CPU map can become invalidated when a batch is flushed out, which + * can happen at unpredictable times. You should use WC maps instead. + */ + assert(bo->cache_coherent || !(flags & MAP_WRITE)); + if (!bo->map_cpu) { struct drm_i915_gem_mmap mmap_arg; void *map;