| Message ID | 20241118033646.31633-1-jason-jh.lin@mediatek.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | drm/mediatek: Add no pending_planes flag checking for mtk_crtc_finish_page_flip() | expand |
Hi, Jason: On Mon, 2024-11-18 at 11:36 +0800, Jason-JH.Lin wrote: > mtk_crtc_finish_page_flip() is used to notify the page flip that has > been completed to the userspace, so userspace can free the frame buffer > of the last frame and commit the next frame. > > However, mtk_crtc_finish_page_flip() cannot guarantee the GCE has > configured all the display hardware settings of the last frame. > This may cause the display hardware to still access the last frame > buffer released by the userspace. > > So add the checking condition of no pending_plens flags to make sure > GCE has executed all the pending planes configuration. What's the probability? If it's low probability, we could drop calling mtk_crtc_finish_page_flip(). If it's not low probability, I think drop calling mtk_crtc_finish_page_flip() would reduce the fps and we should find another way. Regards, CK > > 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 | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/mediatek/mtk_crtc.c b/drivers/gpu/drm/mediatek/mtk_crtc.c > index eb0e1233ad04..b03b9102ff90 100644 > --- a/drivers/gpu/drm/mediatek/mtk_crtc.c > +++ b/drivers/gpu/drm/mediatek/mtk_crtc.c > @@ -113,7 +113,8 @@ static void mtk_drm_finish_page_flip(struct mtk_crtc *mtk_crtc) > 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) { > + if (!mtk_crtc->config_updating && mtk_crtc->pending_needs_vblank && > + !mtk_crtc->pending_planes) { > mtk_crtc_finish_page_flip(mtk_crtc); > mtk_crtc->pending_needs_vblank = false; > }
diff --git a/drivers/gpu/drm/mediatek/mtk_crtc.c b/drivers/gpu/drm/mediatek/mtk_crtc.c index eb0e1233ad04..b03b9102ff90 100644 --- a/drivers/gpu/drm/mediatek/mtk_crtc.c +++ b/drivers/gpu/drm/mediatek/mtk_crtc.c @@ -113,7 +113,8 @@ static void mtk_drm_finish_page_flip(struct mtk_crtc *mtk_crtc) 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) { + if (!mtk_crtc->config_updating && mtk_crtc->pending_needs_vblank && + !mtk_crtc->pending_planes) { mtk_crtc_finish_page_flip(mtk_crtc); mtk_crtc->pending_needs_vblank = false; }
mtk_crtc_finish_page_flip() is used to notify the page flip that has been completed to the userspace, so userspace can free the frame buffer of the last frame and commit the next frame. However, mtk_crtc_finish_page_flip() cannot guarantee the GCE has configured all the display hardware settings of the last frame. This may cause the display hardware to still access the last frame buffer released by the userspace. So add the checking condition of no pending_plens flags to make sure GCE has executed all the pending planes configuration. 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 | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)