[igt-dev] [PATCH i-g-t] i915: Handle the case where legacy mmap is not available

[Dixit, Ashutosh]

On Thu, 24 Jun 2021 02:02:04 -0700, Maarten Lankhorst wrote:
>
> Op 24-06-2021 om 03:30 schreef Dixit, Ashutosh:
> > On Tue, 11 May 2021 02:00:00 -0700, Maarten Lankhorst wrote:
> >> @@ -84,10 +93,14 @@ void *__gem_mmap__gtt(int fd, uint32_t handle, uint64_t size, unsigned prot)
> >>  {
> >>	struct drm_i915_gem_mmap_gtt mmap_arg;
> >>	void *ptr;
> >> +	int ret;
> >>
> >>	memset(&mmap_arg, 0, sizeof(mmap_arg));
> >>	mmap_arg.handle = handle;
> >> -	if (igt_ioctl(fd, DRM_IOCTL_I915_GEM_MMAP_GTT, &mmap_arg))
> >> +	ret = igt_ioctl(fd, DRM_IOCTL_I915_GEM_MMAP_GTT, &mmap_arg);
> >> +	if (ret == -1 && errno == EOPNOTSUPP)
> > What is the handler for DRM_IOCTL_I915_GEM_MMAP_GTT ioctl in i915 (in the
> > kernel)? I am unable to find it so for now I am just assuming that it will
> > just get routed to the handler for DRM_IOCTL_I915_GEM_MMAP and return
> > EOPNOTSUPP for Gen12+ which is what the code above seems to be assuming.
>
> tools/include/uapi/drm/i915_drm.h:#define DRM_IOCTL_I915_GEM_MMAP               DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GEM_MMAP, struct drm_i915_gem_mmap)
> tools/include/uapi/drm/i915_drm.h:#define DRM_IOCTL_I915_GEM_MMAP_GTT   DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GEM_MMAP_GTT, struct drm_i915_gem_mmap_gtt)
> tools/include/uapi/drm/i915_drm.h:#define DRM_IOCTL_I915_GEM_MMAP_OFFSET        DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GEM_MMAP_GTT, struct drm_i915_gem_mmap_offset)
>
> I wasn't aware of that, even..
>
> MMAP_GTT is MMAP_OFFSET with flags and extensions set to 0. Which means
> flags = I915_MMAP_OFFSET_GTT.

Ah, got it! Thanks!