[Mesa-dev] [PATCH 08/11] GLX/DRI3: Add GPU offloading support.
Axel Davy
axel.davy at ens.fr
Thu Jun 19 07:27:43 PDT 2014
I've just noted
I forgot to update the blitImage flags on this patch,
when I use 1 as flush_flag argument it should be replaced by
__BLIT_FLAG_FLUSH.
Axel Davy
On 18/06/2014 23:27, Axel Davy wrote :
> The differences with DRI2 GPU offloading are:
> . There's no logic for GPU offloading needed in the Xserver
> . for DRI2, the card would render to a back buffer, and
> the content would be copied to the front buffer (the same buffers
> everytime). Here we can potentially use several back buffers and copy
> to buffers with no tiling to share with X. We send them with the
> Present extension.
> That means than the DRI2 solution is forced to have tearings with GPU
> offloading. In the ideal scenario, this DRI3 solution doesn't have this
> problem.
> However without dma-buf fences, a race can appear (if the card is slow
> and the rendering hasn't finished before the server card reads the buffer),
> and then old content is displayed. If a user hits this, he should probably
> revert to the DRI2 solution (LIBGL_DRI3_DISABLE). Users with cards fast
> enough seem to not hit this in practice (I have an Amd hd 7730m, and I
> don't hit this, except if I force a low dpm mode)
> . for non-fullscreen apps, the DRI2 GPU offloading solution requires
> compositing. This DRI3 solution doesn't have this requirement. Rendering
> to a pixmap also works.
> . There is no need to have a DDX loaded for the secondary card.
>
> V4: Fixes some piglit tests
>
> Signed-off-by: Axel Davy <axel.davy at ens.fr>
> ---
> src/glx/dri3_glx.c | 236 +++++++++++++++++++++++++++++++++++++++++++---------
> src/glx/dri3_priv.h | 2 +
> 2 files changed, 198 insertions(+), 40 deletions(-)
>
> diff --git a/src/glx/dri3_glx.c b/src/glx/dri3_glx.c
> index b309cd4..f147112 100644
> --- a/src/glx/dri3_glx.c
> +++ b/src/glx/dri3_glx.c
> @@ -596,22 +596,44 @@ dri3_copy_sub_buffer(__GLXDRIdrawable *pdraw, int x, int y,
> {
> struct dri3_drawable *priv = (struct dri3_drawable *) pdraw;
> struct dri3_screen *psc = (struct dri3_screen *) pdraw->psc;
> + struct dri3_context *pcp = (struct dri3_context *) __glXGetCurrentContext();
> xcb_connection_t *c = XGetXCBConnection(priv->base.psc->dpy);
> - struct dri3_buffer *back = dri3_back_buffer(priv);
> + struct dri3_buffer *back;
>
> - unsigned flags;
> + unsigned flags = __DRI2_FLUSH_DRAWABLE;
>
> /* Check we have the right attachments */
> if (!priv->have_back || priv->is_pixmap)
> return;
>
> - flags = __DRI2_FLUSH_DRAWABLE;
> if (flush)
> flags |= __DRI2_FLUSH_CONTEXT;
> dri3_flush(psc, priv, flags, __DRI2_THROTTLE_SWAPBUFFER);
>
> + back = dri3_back_buffer(priv);
> y = priv->height - y - height;
>
> + if (psc->is_different_gpu && (&pcp->base != &dummyContext) && pcp->base.psc == &psc->base) {
> + /* Update the linear buffer part of the back buffer
> + * for the dri3_copy_area operation
> + */
> + psc->image->blitImage(pcp->driContext,
> + back->linear_buffer,
> + back->image,
> + 0, 0, back->width,
> + back->height,
> + 0, 0, back->width,
> + back->height, 1);
> + /* We use blitImage to update our fake front,
> + */
> + if (priv->have_fake_front)
> + psc->image->blitImage(pcp->driContext,
> + dri3_fake_front_buffer(priv)->image,
> + back->image,
> + x, y, width, height,
> + x, y, width, height, 1);
> + }
> +
> dri3_fence_reset(c, back);
> dri3_copy_area(c,
> dri3_back_buffer(priv)->pixmap,
> @@ -622,7 +644,7 @@ dri3_copy_sub_buffer(__GLXDRIdrawable *pdraw, int x, int y,
> /* Refresh the fake front (if present) after we just damaged the real
> * front.
> */
> - if (priv->have_fake_front) {
> + if (priv->have_fake_front && !psc->is_different_gpu) {
> dri3_fence_reset(c, dri3_fake_front_buffer(priv));
> dri3_copy_area(c,
> dri3_back_buffer(priv)->pixmap,
> @@ -655,25 +677,62 @@ dri3_copy_drawable(struct dri3_drawable *priv, Drawable dest, Drawable src)
> static void
> dri3_wait_x(struct glx_context *gc)
> {
> + struct dri3_context *pcp = (struct dri3_context *) gc;
> struct dri3_drawable *priv = (struct dri3_drawable *)
> GetGLXDRIDrawable(gc->currentDpy, gc->currentDrawable);
> + struct dri3_screen *psc;
> + struct dri3_buffer *front;
>
> if (priv == NULL || !priv->have_fake_front)
> return;
>
> - dri3_copy_drawable(priv, dri3_fake_front_buffer(priv)->pixmap, priv->base.xDrawable);
> + psc = (struct dri3_screen *) priv->base.psc;
> + front = dri3_fake_front_buffer(priv);
> +
> + dri3_copy_drawable(priv, front->pixmap, priv->base.xDrawable);
> +
> + /* In the psc->is_different_gpu case, the linear buffer has been updated,
> + * but not yet the tiled buffer.
> + * Copy back to the tiled buffer we use for rendering.
> + * Note that we don't need flushing.
> + */
> + if (psc->is_different_gpu && (&pcp->base != &dummyContext) && pcp->base.psc == &psc->base)
> + psc->image->blitImage(pcp->driContext,
> + front->image,
> + front->linear_buffer,
> + 0, 0, front->width,
> + front->height,
> + 0, 0, front->width,
> + front->height, 0);
> }
>
> static void
> dri3_wait_gl(struct glx_context *gc)
> {
> + struct dri3_context *pcp = (struct dri3_context *) gc;
> struct dri3_drawable *priv = (struct dri3_drawable *)
> GetGLXDRIDrawable(gc->currentDpy, gc->currentDrawable);
> + struct dri3_screen *psc;
> + struct dri3_buffer *front;
>
> if (priv == NULL || !priv->have_fake_front)
> return;
>
> - dri3_copy_drawable(priv, priv->base.xDrawable, dri3_fake_front_buffer(priv)->pixmap);
> + psc = (struct dri3_screen *) priv->base.psc;
> + front = dri3_fake_front_buffer(priv);
> +
> + /* In the psc->is_different_gpu case, we update the linear_buffer
> + * before updating the real front.
> + */
> + if (psc->is_different_gpu && (&pcp->base != &dummyContext) && pcp->base.psc == &psc->base)
> + psc->image->blitImage(pcp->driContext,
> + front->linear_buffer,
> + front->image,
> + 0, 0, front->width,
> + front->height,
> + 0, 0, front->width,
> + front->height, 1);
> + dri3_copy_drawable(priv, priv->base.xDrawable, front->pixmap);
> }
>
> /**
> @@ -741,6 +800,7 @@ dri3_alloc_render_buffer(struct glx_screen *glx_screen, Drawable draw,
> struct dri3_screen *psc = (struct dri3_screen *) glx_screen;
> Display *dpy = glx_screen->dpy;
> struct dri3_buffer *buffer;
> + __DRIimage *pixmap_buffer;
> xcb_connection_t *c = XGetXCBConnection(dpy);
> xcb_pixmap_t pixmap;
> xcb_sync_fence_t sync_fence;
> @@ -769,24 +829,47 @@ dri3_alloc_render_buffer(struct glx_screen *glx_screen, Drawable draw,
> if (!buffer->cpp)
> goto no_image;
>
> - buffer->image = (*psc->image->createImage) (psc->driScreen,
> - width, height,
> - format,
> - __DRI_IMAGE_USE_SHARE|__DRI_IMAGE_USE_SCANOUT,
> - buffer);
> -
> -
> - if (!buffer->image)
> - goto no_image;
> + if (!psc->is_different_gpu) {
> + buffer->image = (*psc->image->createImage) (psc->driScreen,
> + width, height,
> + format,
> + __DRI_IMAGE_USE_SHARE |
> + __DRI_IMAGE_USE_SCANOUT,
> + buffer);
> + pixmap_buffer = buffer->image;
> +
> + if (!buffer->image)
> + goto no_image;
> + } else {
> + buffer->image = (*psc->image->createImage) (psc->driScreen,
> + width, height,
> + format,
> + 0,
> + buffer);
> +
> + if (!buffer->image)
> + goto no_image;
> +
> + buffer->linear_buffer = (*psc->image->createImage) (psc->driScreen,
> + width, height,
> + format,
> + __DRI_IMAGE_USE_SHARE |
> + __DRI_IMAGE_USE_LINEAR,
> + buffer);
> + pixmap_buffer = buffer->linear_buffer;
> +
> + if (!buffer->linear_buffer)
> + goto no_linear_buffer;
> + }
>
> /* X wants the stride, so ask the image for it
> */
> - if (!(*psc->image->queryImage)(buffer->image, __DRI_IMAGE_ATTRIB_STRIDE, &stride))
> + if (!(*psc->image->queryImage)(pixmap_buffer, __DRI_IMAGE_ATTRIB_STRIDE, &stride))
> goto no_buffer_attrib;
>
> buffer->pitch = stride;
>
> - if (!(*psc->image->queryImage)(buffer->image, __DRI_IMAGE_ATTRIB_FD, &buffer_fd))
> + if (!(*psc->image->queryImage)(pixmap_buffer, __DRI_IMAGE_ATTRIB_FD, &buffer_fd))
> goto no_buffer_attrib;
>
> xcb_dri3_pixmap_from_buffer(c,
> @@ -817,7 +900,10 @@ dri3_alloc_render_buffer(struct glx_screen *glx_screen, Drawable draw,
> return buffer;
>
> no_buffer_attrib:
> - (*psc->image->destroyImage)(buffer->image);
> + (*psc->image->destroyImage)(pixmap_buffer);
> +no_linear_buffer:
> + if (psc->is_different_gpu)
> + (*psc->image->destroyImage)(buffer->image);
> no_image:
> free(buffer);
> no_buffer:
> @@ -843,6 +929,8 @@ dri3_free_render_buffer(struct dri3_drawable *pdraw, struct dri3_buffer *buffer)
> xcb_sync_destroy_fence(c, buffer->sync_fence);
> xshmfence_unmap_shm(buffer->shm_fence);
> (*psc->image->destroyImage)(buffer->image);
> + if (buffer->linear_buffer)
> + (*psc->image->destroyImage)(buffer->linear_buffer);
> free(buffer);
> }
>
> @@ -1118,7 +1206,9 @@ dri3_get_buffer(__DRIdrawable *driDrawable,
> enum dri3_buffer_type buffer_type,
> void *loaderPrivate)
> {
> + struct dri3_context *pcp = (struct dri3_context *) __glXGetCurrentContext();
> struct dri3_drawable *priv = loaderPrivate;
> + struct dri3_screen *psc = (struct dri3_screen *) priv->base.psc;
> xcb_connection_t *c = XGetXCBConnection(priv->base.psc->dpy);
> struct dri3_buffer *buffer;
> int buf_id;
> @@ -1154,14 +1244,24 @@ dri3_get_buffer(__DRIdrawable *driDrawable,
> switch (buffer_type) {
> case dri3_buffer_back:
> if (buffer) {
> - dri3_fence_reset(c, new_buffer);
> - dri3_fence_await(c, buffer);
> - dri3_copy_area(c,
> - buffer->pixmap,
> - new_buffer->pixmap,
> - dri3_drawable_gc(priv),
> - 0, 0, 0, 0, priv->width, priv->height);
> + if (!buffer->linear_buffer) {
> + dri3_fence_reset(c, new_buffer);
> + dri3_fence_await(c, buffer);
> + dri3_copy_area(c,
> + buffer->pixmap,
> + new_buffer->pixmap,
> + dri3_drawable_gc(priv),
> + 0, 0, 0, 0, priv->width, priv->height);
> dri3_fence_trigger(c, new_buffer);
> + } else if ((&pcp->base != &dummyContext) && pcp->base.psc == &psc->base) {
> + psc->image->blitImage(pcp->driContext,
> + new_buffer->image,
> + buffer->image,
> + 0, 0, priv->width,
> + priv->height,
> + 0, 0, priv->width,
> + priv->height, 0);
> + }
> dri3_free_render_buffer(priv, buffer);
> }
> break;
> @@ -1173,6 +1273,17 @@ dri3_get_buffer(__DRIdrawable *driDrawable,
> dri3_drawable_gc(priv),
> 0, 0, 0, 0, priv->width, priv->height);
> dri3_fence_trigger(c, new_buffer);
> +
> + if (new_buffer->linear_buffer && (&pcp->base != &dummyContext) && pcp->base.psc == &psc->base) {
> + dri3_fence_await(c, new_buffer);
> + psc->image->blitImage(pcp->driContext,
> + new_buffer->image,
> + new_buffer->linear_buffer,
> + 0, 0, priv->width,
> + priv->height,
> + 0, 0, priv->width,
> + priv->height, 0);
> + }
> break;
> }
> buffer = new_buffer;
> @@ -1235,6 +1346,7 @@ dri3_get_buffers(__DRIdrawable *driDrawable,
> struct __DRIimageList *buffers)
> {
> struct dri3_drawable *priv = loaderPrivate;
> + struct dri3_screen *psc = (struct dri3_screen *) priv->base.psc;
> struct dri3_buffer *front, *back;
>
> buffers->image_mask = 0;
> @@ -1252,7 +1364,15 @@ dri3_get_buffers(__DRIdrawable *driDrawable,
> buffer_mask |= __DRI_IMAGE_BUFFER_FRONT;
>
> if (buffer_mask & __DRI_IMAGE_BUFFER_FRONT) {
> - if (priv->is_pixmap)
> + /* All pixmaps are owned by the server gpu.
> + * When we use a different gpu, we can't use the pixmap
> + * as buffer since it is potentially tiled a way
> + * our device can't understand. In this case, use
> + * a fake front buffer. Hopefully the pixmap
> + * content will get synced with the fake front
> + * buffer.
> + */
> + if (priv->is_pixmap && !psc->is_different_gpu)
> front = dri3_get_pixmap_buffer(driDrawable,
> format,
> dri3_buffer_front,
> @@ -1286,7 +1406,7 @@ dri3_get_buffers(__DRIdrawable *driDrawable,
> if (front) {
> buffers->image_mask |= __DRI_IMAGE_BUFFER_FRONT;
> buffers->front = front->image;
> - priv->have_fake_front = !priv->is_pixmap;
> + priv->have_fake_front = psc->is_different_gpu || !priv->is_pixmap;
> }
>
> if (back) {
> @@ -1327,11 +1447,12 @@ static int64_t
> dri3_swap_buffers(__GLXDRIdrawable *pdraw, int64_t target_msc, int64_t divisor,
> int64_t remainder, Bool flush)
> {
> + struct dri3_context *pcp = (struct dri3_context *) __glXGetCurrentContext();
> struct dri3_drawable *priv = (struct dri3_drawable *) pdraw;
> struct dri3_screen *psc = (struct dri3_screen *) priv->base.psc;
> Display *dpy = priv->base.psc->dpy;
> xcb_connection_t *c = XGetXCBConnection(dpy);
> - int buf_id = DRI3_BACK_ID(priv->cur_back);
> + struct dri3_buffer *back;
> int64_t ret = 0;
>
> unsigned flags = __DRI2_FLUSH_DRAWABLE;
> @@ -1339,10 +1460,32 @@ dri3_swap_buffers(__GLXDRIdrawable *pdraw, int64_t target_msc, int64_t divisor,
> flags |= __DRI2_FLUSH_CONTEXT;
> dri3_flush(psc, priv, flags, __DRI2_THROTTLE_SWAPBUFFER);
>
> + back = priv->buffers[DRI3_BACK_ID(priv->cur_back)];
> +
> + if (psc->is_different_gpu && back) {
> + /* Update the linear buffer before presenting the pixmap */
> + psc->image->blitImage(pcp->driContext,
> + back->linear_buffer,
> + back->image,
> + 0, 0, back->width,
> + back->height,
> + 0, 0, back->width,
> + back->height, 1);
> + /* Update the fake front */
> + if (priv->have_fake_front)
> + psc->image->blitImage(pcp->driContext,
> + priv->buffers[DRI3_FRONT_ID]->image,
> + back->image,
> + 0, 0, priv->width,
> + priv->height,
> + 0, 0, priv->width,
> + priv->height, 1);
> + }
> +
> dri3_flush_present_events(priv);
>
> - if (priv->buffers[buf_id] && !priv->is_pixmap) {
> - dri3_fence_reset(c, priv->buffers[buf_id]);
> + if (back && !priv->is_pixmap) {
> + dri3_fence_reset(c, back);
>
> /* Compute when we want the frame shown by taking the last known successful
> * MSC and adding in a swap interval for each outstanding swap request
> @@ -1351,11 +1494,11 @@ dri3_swap_buffers(__GLXDRIdrawable *pdraw, int64_t target_msc, int64_t divisor,
> if (target_msc == 0)
> target_msc = priv->msc + priv->swap_interval * (priv->send_sbc - priv->recv_sbc);
>
> - priv->buffers[buf_id]->busy = 1;
> - priv->buffers[buf_id]->last_swap = priv->send_sbc;
> + back->busy = 1;
> + back->last_swap = priv->send_sbc;
> xcb_present_pixmap(c,
> priv->base.xDrawable,
> - priv->buffers[buf_id]->pixmap,
> + back->pixmap,
> (uint32_t) priv->send_sbc,
> 0, /* valid */
> 0, /* update */
> @@ -1363,7 +1506,7 @@ dri3_swap_buffers(__GLXDRIdrawable *pdraw, int64_t target_msc, int64_t divisor,
> 0, /* y_off */
> None, /* target_crtc */
> None,
> - priv->buffers[buf_id]->sync_fence,
> + back->sync_fence,
> XCB_PRESENT_OPTION_NONE,
> target_msc,
> divisor,
> @@ -1375,10 +1518,10 @@ dri3_swap_buffers(__GLXDRIdrawable *pdraw, int64_t target_msc, int64_t divisor,
> * to reset the fence and make future users block until
> * the X server is done copying the bits
> */
> - if (priv->have_fake_front) {
> + if (priv->have_fake_front && !psc->is_different_gpu) {
> dri3_fence_reset(c, priv->buffers[DRI3_FRONT_ID]);
> dri3_copy_area(c,
> - priv->buffers[buf_id]->pixmap,
> + back->pixmap,
> priv->buffers[DRI3_FRONT_ID]->pixmap,
> dri3_drawable_gc(priv),
> 0, 0, 0, 0, priv->width, priv->height);
> @@ -1591,7 +1734,12 @@ dri3_bind_extensions(struct dri3_screen *psc, struct glx_display * priv,
> "GLX_EXT_create_context_es2_profile");
>
> for (i = 0; extensions[i]; i++) {
> - if ((strcmp(extensions[i]->name, __DRI_TEX_BUFFER) == 0)) {
> + /* when on a different gpu than the server, the server pixmaps
> + * can have a tiling mode we can't read. Thus we can't create
> + * a texture from them.
> + */
> + if (!psc->is_different_gpu &&
> + (strcmp(extensions[i]->name, __DRI_TEX_BUFFER) == 0)) {
> psc->texBuffer = (__DRItexBufferExtension *) extensions[i];
> __glXEnableDirectExtension(&psc->base, "GLX_EXT_texture_from_pixmap");
> }
> @@ -1672,6 +1820,8 @@ dri3_create_screen(int screen, struct glx_display * priv)
>
> return NULL;
> }
> +
> + psc->fd = loader_get_user_preferred_fd(psc->fd, &psc->is_different_gpu);
> deviceName = NULL;
>
> driverName = loader_get_driver_for_fd(psc->fd, 0);
> @@ -1738,9 +1888,15 @@ dri3_create_screen(int screen, struct glx_display * priv)
> goto handle_error;
> }
>
> - if (!psc->texBuffer || psc->texBuffer->base.version < 2 ||
> - !psc->texBuffer->setTexBuffer2)
> - {
> + if (psc->is_different_gpu && psc->image->base.version < 9) {
> + ErrorMessageF("Different GPU, but image extension version 9 or later not found\n");
> + goto handle_error;
> + }
> +
> + if (!psc->is_different_gpu && (
> + !psc->texBuffer || psc->texBuffer->base.version < 2 ||
> + !psc->texBuffer->setTexBuffer2
> + )) {
> ErrorMessageF("Version 2 or later of texBuffer extension not found\n");
> goto handle_error;
> }
> diff --git a/src/glx/dri3_priv.h b/src/glx/dri3_priv.h
> index 6894886..c0e35ee 100644
> --- a/src/glx/dri3_priv.h
> +++ b/src/glx/dri3_priv.h
> @@ -72,6 +72,7 @@ enum dri3_buffer_type {
>
> struct dri3_buffer {
> __DRIimage *image;
> + __DRIimage *linear_buffer;
> uint32_t pixmap;
>
> /* Synchronization between the client and X server is done using an
> @@ -135,6 +136,7 @@ struct dri3_screen {
>
> void *driver;
> int fd;
> + int is_different_gpu;
>
> Bool show_fps;
> };
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