Re: [PATCH 4/6] drm: vkms: Add fb information to `vkms_writeback_job`

Hi

Am 05.10.21 um 22:16 schrieb Igor Matheus Andrade Torrente:

This commit is the groundwork to introduce new formats to the planes and writeback buffer. As part of it, a new buffer metadata field is added to `vkms_writeback_job`, this metadata is represented by the `vkms_composer` struct.

This will allow us, in the future, to have different compositing and wb format types.

Signed-off-by: Igor Matheus Andrade Torrente igormtorrente@gmail.com

drivers/gpu/drm/vkms/vkms_drv.h | 10 +++++----- drivers/gpu/drm/vkms/vkms_writeback.c | 16 +++++++++++++--- 2 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h index 64e62993b06f..d62f8ebd454b 100644 --- a/drivers/gpu/drm/vkms/vkms_drv.h +++ b/drivers/gpu/drm/vkms/vkms_drv.h @@ -20,11 +20,6 @@ #define XRES_MAX 8192 #define YRES_MAX 8192

-struct vkms_writeback_job {

• struct dma_buf_map map[DRM_FORMAT_MAX_PLANES];
• struct dma_buf_map data[DRM_FORMAT_MAX_PLANES];

-};

• struct vkms_composer { struct drm_framebuffer fb; struct drm_rect src, dst;

@@ -34,6 +29,11 @@ struct vkms_composer { unsigned int cpp; };

+struct vkms_writeback_job {

• struct dma_buf_map data[DRM_FORMAT_MAX_PLANES];
• struct vkms_composer composer;

+};

• /**
  • vkms_plane_state - Driver specific plane state
  • @base: base plane state

diff --git a/drivers/gpu/drm/vkms/vkms_writeback.c b/drivers/gpu/drm/vkms/vkms_writeback.c index 8694227f555f..5a3e12f105dc 100644 --- a/drivers/gpu/drm/vkms/vkms_writeback.c +++ b/drivers/gpu/drm/vkms/vkms_writeback.c @@ -75,7 +75,7 @@ static int vkms_wb_prepare_job(struct drm_writeback_connector *wb_connector, if (!vkmsjob) return -ENOMEM;

• ret = drm_gem_fb_vmap(job->fb, vkmsjob->map, vkmsjob->data);

• ret = drm_gem_fb_vmap(job->fb, vkmsjob->composer.map, vkmsjob->data); if (ret) { DRM_ERROR("vmap failed: %d\n", ret); goto err_kfree;

@@ -99,7 +99,7 @@ static void vkms_wb_cleanup_job(struct drm_writeback_connector *connector, if (!job->fb) return;

• drm_gem_fb_vunmap(job->fb, vkmsjob->map);

• drm_gem_fb_vunmap(job->fb, vkmsjob->composer.map);

  vkmsdev = drm_device_to_vkms_device(job->fb->dev); vkms_set_composer(&vkmsdev->output, false);

@@ -116,14 +116,24 @@ static void vkms_wb_atomic_commit(struct drm_connector *conn, struct drm_writeback_connector *wb_conn = &output->wb_connector; struct drm_connector_state *conn_state = wb_conn->base.state; struct vkms_crtc_state *crtc_state = output->composer_state;

• struct drm_framebuffer *fb = connector_state->writeback_job->fb;

• struct vkms_writeback_job *active_wb;

• struct vkms_composer *wb_composer;

  if (!conn_state) return;

  vkms_set_composer(&vkmsdev->output, true);

• active_wb = conn_state->writeback_job->priv;

• wb_composer = &active_wb->composer;

• spin_lock_irq(&output->composer_lock);

• crtc_state->active_writeback = conn_state->writeback_job->priv;

• crtc_state->active_writeback = active_wb;
• memcpy(&wb_composer->fb, fb, sizeof(struct drm_framebuffer));
• wb_composer->offset = fb->offsets[0];
• wb_composer->pitch = fb->pitches[0];
• wb_composer->cpp = fb->format->cpp[0];

I don't know the exact cleanup requirements of these structures, but copying fb into composer looks like it breaks reference counting of the framebuffer's gem objects at least.

This atomic_commit helper would better acquire the correct references and hand them over to the compositor thread. Why not have a ref-counted composer or get a reference on the framebuffer instead?

Best regards Thomas

crtc_state->wb_pending = true; spin_unlock_irq(&output->composer_lock); drm_writeback_queue_job(wb_conn, connector_state);