<html><body><p> <pre> Hi, Jason: On Wed, 2024-11-20 at 00:36 +0800, Jason-JH.Lin wrote: > mtk_crtc_finish_page_flip() is used to notify userspace that a > page flip has been completed, allowing userspace to free the frame > buffer of the last frame and commit the next frame. > > In MediaTek's hardware design for configuring display hardware by using > GCE, `DRM_EVENT_FLIP_COMPLETE` should be notified to userspace after > GCE has finished configuring all display hardware settings for each > atomic_commit(). > > Currently, mtk_crtc_finish_page_flip() cannot guarantee that GCE has > configured all the display hardware settings of the last frame. > Therefore, to increase the accuracy of the timing for notifying > `DRM_EVENT_FLIP_COMPLETE` to userspace, mtk_crtc_finish_page_flip() > should be moved to ddp_cmdq_cb(). > > Fixes: 7f82d9c43879 ("drm/mediatek: Clear pending flag when cmdq packet is done") > Signed-off-by: Jason-JH.Lin <jason-jh.lin@mediatek.com> > --- > drivers/gpu/drm/mediatek/mtk_crtc.c | 27 +++++++++++++++++---------- > 1 file changed, 17 insertions(+), 10 deletions(-) > > diff --git a/drivers/gpu/drm/mediatek/mtk_crtc.c b/drivers/gpu/drm/mediatek/mtk_crtc.c > index eb0e1233ad04..0d57863c075a 100644 > --- a/drivers/gpu/drm/mediatek/mtk_crtc.c > +++ b/drivers/gpu/drm/mediatek/mtk_crtc.c > @@ -109,15 +109,19 @@ static void mtk_crtc_finish_page_flip(struct mtk_crtc *mtk_crtc) > static void mtk_drm_finish_page_flip(struct mtk_crtc *mtk_crtc) > { > unsigned long flags; > +struct drm_crtc *crtc = &mtk_crtc->base; > +struct mtk_drm_private *priv = crtc->dev->dev_private; > > drm_crtc_handle_vblank(&mtk_crtc->base); > > -spin_lock_irqsave(&mtk_crtc->config_lock, flags); > -if (!mtk_crtc->config_updating && mtk_crtc->pending_needs_vblank) { > -mtk_crtc_finish_page_flip(mtk_crtc); > -mtk_crtc->pending_needs_vblank = false; > +if (priv->data->shadow_register) { if (!priv->data->shadow_register) return; And this would reduce the indent. > +spin_lock_irqsave(&mtk_crtc->config_lock, flags); > +if (!mtk_crtc->config_updating && mtk_crtc->pending_needs_vblank) { > +mtk_crtc_finish_page_flip(mtk_crtc); > +mtk_crtc->pending_needs_vblank = false; > +} > +spin_unlock_irqrestore(&mtk_crtc->config_lock, flags); > } > -spin_unlock_irqrestore(&mtk_crtc->config_lock, flags); > } > > static void mtk_crtc_destroy(struct drm_crtc *crtc) > @@ -284,10 +288,8 @@ static void ddp_cmdq_cb(struct mbox_client *cl, void *mssg) > state = to_mtk_crtc_state(mtk_crtc->base.state); > > spin_lock_irqsave(&mtk_crtc->config_lock, flags); > -if (mtk_crtc->config_updating) { > -spin_unlock_irqrestore(&mtk_crtc->config_lock, flags); > +if (mtk_crtc->config_updating) > goto ddp_cmdq_cb_out; > -} > > state->pending_config = false; > > @@ -315,10 +317,15 @@ static void ddp_cmdq_cb(struct mbox_client *cl, void *mssg) > mtk_crtc->pending_async_planes = false; > } > > -spin_unlock_irqrestore(&mtk_crtc->config_lock, flags); > - > ddp_cmdq_cb_out: > > +if (mtk_crtc->pending_needs_vblank) { > +mtk_crtc_finish_page_flip(mtk_crtc); > +mtk_crtc->pending_needs_vblank = false; In mtk_crtc_update_config(), after mbox_client_txdone() and before mtk_crtc->config_updating = false; cmdq may have finish the command and callback ddp_cmdq_cb(). Because mtk_crtc->config_updating is true, so this page flip would be skipped. But if there is no next mtk_crtc_update_config() exist, this page flip would never happen. This may cause some deadlock. Regards, CK > +} > + > +spin_unlock_irqrestore(&mtk_crtc->config_lock, flags); > + > mtk_crtc->cmdq_vblank_cnt = 0; > wake_up(&mtk_crtc->cb_blocking_queue); > } </pre> </p></body></html><pre>************* MEDIATEK Confidentiality Notice ******************** The information contained in this e-mail message (including any attachments) may be confidential, proprietary, privileged, or otherwise exempt from disclosure under applicable laws. It is intended to be conveyed only to the designated recipient(s). Any use, dissemination, distribution, printing, retaining or copying of this e-mail (including its attachments) by unintended recipient(s) is strictly prohibited and may be unlawful. If you are not an intended recipient of this e-mail, or believe that you have received this e-mail in error, please notify the sender immediately (by replying to this e-mail), delete any and all copies of this e-mail (including any attachments) from your system, and do not disclose the content of this e-mail to any other person. Thank you! </pre>