diff options
| -rw-r--r-- | drivers/gpu/drm/i915/i915_gem.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index e9c783d55612..895f9881f0aa 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -1466,6 +1466,16 @@ unlock: * * While the mapping holds a reference on the contents of the object, it doesn't * imply a ref on the object itself. + * + * IMPORTANT: + * + * DRM driver writers who look a this function as an example for how to do GEM + * mmap support, please don't implement mmap support like here. The modern way + * to implement DRM mmap support is with an mmap offset ioctl (like + * i915_gem_mmap_gtt) and then using the mmap syscall on the DRM fd directly. + * That way debug tooling like valgrind will understand what's going on, hiding + * the mmap call in a driver private ioctl will break that. The i915 driver only + * does cpu mmaps this way because we didn't know better. */ int i915_gem_mmap_ioctl(struct drm_device *dev, void *data, |