On Tue, 2 Jul 2019 06:56:50 -0700
Alyssa Rosenzweig <alyssa.rosenzw...@collabora.com> wrote:
> Question: Does this allow us to map arbitrary CPU buffers into GPU
> space?
Depends what you mean by arbitrary. You can map any dmabuf, that means
the buffer has to be created kernel side and exported as a DMAbuf.
> Stuff with no relation to the winsys, just... arbitrary user
> memory?
Nope, I don't think so. That might work if you allocate things through
udmabuf, but then you're better off allocating a BO directly.
> That might be useful for index/vertex buffers (which we
> currently are forced to memcpy() into a BO we create if given a user
> pointer rather than a resource), but maybe not actually because of sync
> requirements.
>
> On Tue, Jul 02, 2019 at 03:23:49PM +0200, Boris Brezillon wrote:
> > Let's keep a clear split between ioctl wrappers and the rest of the
> > driver. All the import BO function need is a dmabuf FD and the screen
> > object, and the export one should only take care of generating a dmabuf
> > FD out of a BO object. Winsys handle manipulation should stay in the
> > resource.c file.
> >
> > Signed-off-by: Boris Brezillon <boris.brezil...@collabora.com>
> > ---
> > src/gallium/drivers/panfrost/pan_drm.c | 17 +++++++----------
> > src/gallium/drivers/panfrost/pan_resource.c | 16 +++++++++++-----
> > src/gallium/drivers/panfrost/pan_screen.h | 6 ++----
> > 3 files changed, 20 insertions(+), 19 deletions(-)
> >
> > diff --git a/src/gallium/drivers/panfrost/pan_drm.c
> > b/src/gallium/drivers/panfrost/pan_drm.c
> > index f17f56bc6307..b88ab0e5ce2b 100644
> > --- a/src/gallium/drivers/panfrost/pan_drm.c
> > +++ b/src/gallium/drivers/panfrost/pan_drm.c
> > @@ -114,7 +114,7 @@ panfrost_drm_free_slab(struct panfrost_screen *screen,
> > struct panfrost_memory *m
> > }
> >
> > struct panfrost_bo *
> > -panfrost_drm_import_bo(struct panfrost_screen *screen, struct
> > winsys_handle *whandle)
> > +panfrost_drm_import_bo(struct panfrost_screen *screen, int fd)
> > {
> > struct panfrost_bo *bo = rzalloc(screen, struct panfrost_bo);
> > struct drm_panfrost_get_bo_offset get_bo_offset = {0,};
> > @@ -122,7 +122,7 @@ panfrost_drm_import_bo(struct panfrost_screen *screen,
> > struct winsys_handle *wha
> > int ret;
> > unsigned gem_handle;
> >
> > - ret = drmPrimeFDToHandle(screen->fd, whandle->handle, &gem_handle);
> > + ret = drmPrimeFDToHandle(screen->fd, fd, &gem_handle);
> > assert(!ret);
> >
> > get_bo_offset.handle = gem_handle;
> > @@ -141,7 +141,7 @@ panfrost_drm_import_bo(struct panfrost_screen *screen,
> > struct winsys_handle *wha
> > assert(0);
> > }
> >
> > - bo->size = lseek(whandle->handle, 0, SEEK_END);
> > + bo->size = lseek(fd, 0, SEEK_END);
> > assert(bo->size > 0);
> > bo->cpu = os_mmap(NULL, bo->size, PROT_READ | PROT_WRITE,
> > MAP_SHARED,
> > screen->fd, mmap_bo.offset);
> > @@ -158,21 +158,18 @@ panfrost_drm_import_bo(struct panfrost_screen
> > *screen, struct winsys_handle *wha
> > }
> >
> > int
> > -panfrost_drm_export_bo(struct panfrost_screen *screen, int gem_handle,
> > unsigned int stride, struct winsys_handle *whandle)
> > +panfrost_drm_export_bo(struct panfrost_screen *screen, const struct
> > panfrost_bo *bo)
> > {
> > struct drm_prime_handle args = {
> > - .handle = gem_handle,
> > + .handle = bo->gem_handle,
> > .flags = DRM_CLOEXEC,
> > };
> >
> > int ret = drmIoctl(screen->fd, DRM_IOCTL_PRIME_HANDLE_TO_FD,
> > &args);
> > if (ret == -1)
> > - return FALSE;
> > + return -1;
> >
> > - whandle->handle = args.fd;
> > - whandle->stride = stride;
> > -
> > - return TRUE;
> > + return args.fd;
> > }
> >
> > static int
> > diff --git a/src/gallium/drivers/panfrost/pan_resource.c
> > b/src/gallium/drivers/panfrost/pan_resource.c
> > index 8901aeee09b1..f86617f80c20 100644
> > --- a/src/gallium/drivers/panfrost/pan_resource.c
> > +++ b/src/gallium/drivers/panfrost/pan_resource.c
> > @@ -70,7 +70,7 @@ panfrost_resource_from_handle(struct pipe_screen *pscreen,
> > pipe_reference_init(&prsc->reference, 1);
> > prsc->screen = pscreen;
> >
> > - rsc->bo = panfrost_drm_import_bo(screen, whandle);
> > + rsc->bo = panfrost_drm_import_bo(screen, whandle->handle);
> > rsc->slices[0].stride = whandle->stride;
> > rsc->slices[0].initialized = true;
> >
> > @@ -120,10 +120,16 @@ panfrost_resource_get_handle(struct pipe_screen
> > *pscreen,
> > handle->handle = args.fd;
> >
> > return TRUE;
> > - } else
> > - return panfrost_drm_export_bo(screen,
> > rsrc->bo->gem_handle,
> > -
> > rsrc->slices[0].stride,
> > - handle);
> > + } else {
> > + int fd = panfrost_drm_export_bo(screen, rsrc->bo);
> > +
> > + if (fd < 0)
> > + return FALSE;
> > +
> > + handle->handle = fd;
> > + handle->stride = rsrc->slices[0].stride;
> > + return TRUE;
> > + }
> > }
> >
> > return FALSE;
> > diff --git a/src/gallium/drivers/panfrost/pan_screen.h
> > b/src/gallium/drivers/panfrost/pan_screen.h
> > index 83186ebb2f7f..1a1eb2f8bf27 100644
> > --- a/src/gallium/drivers/panfrost/pan_screen.h
> > +++ b/src/gallium/drivers/panfrost/pan_screen.h
> > @@ -83,11 +83,9 @@ void
> > panfrost_drm_free_slab(struct panfrost_screen *screen,
> > struct panfrost_memory *mem);
> > struct panfrost_bo *
> > -panfrost_drm_import_bo(struct panfrost_screen *screen,
> > - struct winsys_handle *whandle);
> > +panfrost_drm_import_bo(struct panfrost_screen *screen, int fd);
> > int
> > -panfrost_drm_export_bo(struct panfrost_screen *screen, int gem_handle,
> > - unsigned int stride, struct winsys_handle *whandle);
> > +panfrost_drm_export_bo(struct panfrost_screen *screen, const struct
> > panfrost_bo *bo);
> > int
> > panfrost_drm_submit_vs_fs_job(struct panfrost_context *ctx, bool has_draws,
> > bool is_scanout);
> > --
> > 2.21.0
> >
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