2021-10-27 21:22:43

by Fei Shao

[permalink] [raw]
Subject: Re: [PATCH v5 3/6] drm/mediatek: Detect CMDQ execution timeout

Hi Jason,

On Wed, Oct 27, 2021 at 10:19 AM jason-jh.lin <[email protected]> wrote:
>
> From: Chun-Kuang Hu <[email protected]>
>
> CMDQ is used to update display register in vblank period, so
> it should be execute in next 2 vblank. One vblank interrupt
> before send message (occasionally) and one vblank interrupt
> after cmdq done. If it fail to execute in next 3 vblank,
> tiemout happen.
>
> Signed-off-by: Chun-Kuang Hu <[email protected]>
> Signed-off-by: jason-jh.lin <[email protected]>
> Reviewed-by: Chun-Kuang Hu <[email protected]>
> ---
> drivers/gpu/drm/mediatek/mtk_drm_crtc.c | 20 ++++++++++++++++++--
> 1 file changed, 18 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> index e23e3224ac67..dad1f85ee315 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> @@ -54,6 +54,7 @@ struct mtk_drm_crtc {
> #if IS_REACHABLE(CONFIG_MTK_CMDQ)
> struct cmdq_client cmdq_client;
> u32 cmdq_event;
> + u32 cmdq_vblank_cnt;
> #endif
>
> struct device *mmsys_dev;
> @@ -227,7 +228,10 @@ struct mtk_ddp_comp *mtk_drm_ddp_comp_for_plane(struct drm_crtc *crtc,
> static void ddp_cmdq_cb(struct mbox_client *cl, void *mssg)
> {
> struct cmdq_cb_data *data = mssg;
> + struct cmdq_client *cmdq_cl = container_of(cl, struct cmdq_client, client);
> + struct mtk_drm_crtc *mtk_crtc = container_of(cmdq_cl, struct mtk_drm_crtc, cmdq_client);
>
> + mtk_crtc->cmdq_vblank_cnt = 0;
> cmdq_pkt_destroy(data->pkt);
> }
> #endif
> @@ -483,6 +487,15 @@ static void mtk_drm_crtc_update_config(struct mtk_drm_crtc *mtk_crtc,
> cmdq_handle->pa_base,
> cmdq_handle->cmd_buf_size,
> DMA_TO_DEVICE);
> + /*
> + * CMDQ command should execute in next 3 vblank.
> + * One vblank interrupt before send message (occasionally)
> + * and one vblank interrupt after cmdq done,
> + * so it's timeout after 3 vblank interrupt.
> + * If it fail to execute in next 3 vblank, timeout happen.
> + */
> + mtk_crtc->cmdq_vblank_cnt = 3;
> +
> mbox_send_message(mtk_crtc->cmdq_client.chan, cmdq_handle);
> mbox_client_txdone(mtk_crtc->cmdq_client.chan, 0);
> }
> @@ -499,11 +512,14 @@ static void mtk_crtc_ddp_irq(void *data)
>
> #if IS_REACHABLE(CONFIG_MTK_CMDQ)
> if (!priv->data->shadow_register && !mtk_crtc->cmdq_client.chan)
> + mtk_crtc_ddp_config(crtc, NULL);
> + else if (mtk_crtc->cmdq_vblank_cnt > 0 && --mtk_crtc->cmdq_vblank_cnt == 0)
I think atomic_dec_and_test() does what you want to do here.




> + DRM_ERROR("mtk_crtc %d CMDQ execute command timeout!\n",
> + drm_crtc_index(&mtk_crtc->base));
> #else
> if (!priv->data->shadow_register)
> -#endif
> mtk_crtc_ddp_config(crtc, NULL);
> -
> +#endif
> mtk_drm_finish_page_flip(mtk_crtc);
> }
>
> --
> 2.18.0
>


2021-10-27 23:50:25

by Chun-Kuang Hu

[permalink] [raw]
Subject: Re: [PATCH v5 3/6] drm/mediatek: Detect CMDQ execution timeout

Hi, Fei:

Fei Shao <[email protected]> 於 2021年10月27日 週三 下午5:32寫道:
>
> Hi Jason,
>
> On Wed, Oct 27, 2021 at 10:19 AM jason-jh.lin <[email protected]> wrote:
> >
> > From: Chun-Kuang Hu <[email protected]>
> >
> > CMDQ is used to update display register in vblank period, so
> > it should be execute in next 2 vblank. One vblank interrupt
> > before send message (occasionally) and one vblank interrupt
> > after cmdq done. If it fail to execute in next 3 vblank,
> > tiemout happen.
> >
> > Signed-off-by: Chun-Kuang Hu <[email protected]>
> > Signed-off-by: jason-jh.lin <[email protected]>
> > Reviewed-by: Chun-Kuang Hu <[email protected]>
> > ---
> > drivers/gpu/drm/mediatek/mtk_drm_crtc.c | 20 ++++++++++++++++++--
> > 1 file changed, 18 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> > index e23e3224ac67..dad1f85ee315 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> > @@ -54,6 +54,7 @@ struct mtk_drm_crtc {
> > #if IS_REACHABLE(CONFIG_MTK_CMDQ)
> > struct cmdq_client cmdq_client;
> > u32 cmdq_event;
> > + u32 cmdq_vblank_cnt;
> > #endif
> >
> > struct device *mmsys_dev;
> > @@ -227,7 +228,10 @@ struct mtk_ddp_comp *mtk_drm_ddp_comp_for_plane(struct drm_crtc *crtc,
> > static void ddp_cmdq_cb(struct mbox_client *cl, void *mssg)
> > {
> > struct cmdq_cb_data *data = mssg;
> > + struct cmdq_client *cmdq_cl = container_of(cl, struct cmdq_client, client);
> > + struct mtk_drm_crtc *mtk_crtc = container_of(cmdq_cl, struct mtk_drm_crtc, cmdq_client);
> >
> > + mtk_crtc->cmdq_vblank_cnt = 0;
> > cmdq_pkt_destroy(data->pkt);
> > }
> > #endif
> > @@ -483,6 +487,15 @@ static void mtk_drm_crtc_update_config(struct mtk_drm_crtc *mtk_crtc,
> > cmdq_handle->pa_base,
> > cmdq_handle->cmd_buf_size,
> > DMA_TO_DEVICE);
> > + /*
> > + * CMDQ command should execute in next 3 vblank.
> > + * One vblank interrupt before send message (occasionally)
> > + * and one vblank interrupt after cmdq done,
> > + * so it's timeout after 3 vblank interrupt.
> > + * If it fail to execute in next 3 vblank, timeout happen.
> > + */
> > + mtk_crtc->cmdq_vblank_cnt = 3;
> > +
> > mbox_send_message(mtk_crtc->cmdq_client.chan, cmdq_handle);
> > mbox_client_txdone(mtk_crtc->cmdq_client.chan, 0);
> > }
> > @@ -499,11 +512,14 @@ static void mtk_crtc_ddp_irq(void *data)
> >
> > #if IS_REACHABLE(CONFIG_MTK_CMDQ)
> > if (!priv->data->shadow_register && !mtk_crtc->cmdq_client.chan)
> > + mtk_crtc_ddp_config(crtc, NULL);
> > + else if (mtk_crtc->cmdq_vblank_cnt > 0 && --mtk_crtc->cmdq_vblank_cnt == 0)
> I think atomic_dec_and_test() does what you want to do here.

I think this operation is not necessary to be atomic operation, and
this statement could be reduced to

else if (--mtk_crtc->cmdq_vblank_cnt == 0)

>
>
>
>
> > + DRM_ERROR("mtk_crtc %d CMDQ execute command timeout!\n",
> > + drm_crtc_index(&mtk_crtc->base));
> > #else
> > if (!priv->data->shadow_register)
> > -#endif
> > mtk_crtc_ddp_config(crtc, NULL);
> > -
> > +#endif
> > mtk_drm_finish_page_flip(mtk_crtc);
> > }
> >
> > --
> > 2.18.0
> >

2021-10-28 03:21:17

by Fei Shao

[permalink] [raw]
Subject: Re: [PATCH v5 3/6] drm/mediatek: Detect CMDQ execution timeout

Hi Chun-Kuang,

On Thu, Oct 28, 2021 at 7:47 AM Chun-Kuang Hu <[email protected]> wrote:
>
> Hi, Fei:
>
> Fei Shao <[email protected]> 於 2021年10月27日 週三 下午5:32寫道:
> >
> > Hi Jason,
> >
> > On Wed, Oct 27, 2021 at 10:19 AM jason-jh.lin <[email protected]> wrote:
> > >
> > > From: Chun-Kuang Hu <[email protected]>
> > >
> > > CMDQ is used to update display register in vblank period, so
> > > it should be execute in next 2 vblank. One vblank interrupt
> > > before send message (occasionally) and one vblank interrupt
> > > after cmdq done. If it fail to execute in next 3 vblank,
> > > tiemout happen.
> > >
> > > Signed-off-by: Chun-Kuang Hu <[email protected]>
> > > Signed-off-by: jason-jh.lin <[email protected]>
> > > Reviewed-by: Chun-Kuang Hu <[email protected]>
> > > ---
> > > drivers/gpu/drm/mediatek/mtk_drm_crtc.c | 20 ++++++++++++++++++--
> > > 1 file changed, 18 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> > > index e23e3224ac67..dad1f85ee315 100644
> > > --- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> > > +++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> > > @@ -54,6 +54,7 @@ struct mtk_drm_crtc {
> > > #if IS_REACHABLE(CONFIG_MTK_CMDQ)
> > > struct cmdq_client cmdq_client;
> > > u32 cmdq_event;
> > > + u32 cmdq_vblank_cnt;
> > > #endif
> > >
> > > struct device *mmsys_dev;
> > > @@ -227,7 +228,10 @@ struct mtk_ddp_comp *mtk_drm_ddp_comp_for_plane(struct drm_crtc *crtc,
> > > static void ddp_cmdq_cb(struct mbox_client *cl, void *mssg)
> > > {
> > > struct cmdq_cb_data *data = mssg;
> > > + struct cmdq_client *cmdq_cl = container_of(cl, struct cmdq_client, client);
> > > + struct mtk_drm_crtc *mtk_crtc = container_of(cmdq_cl, struct mtk_drm_crtc, cmdq_client);
> > >
> > > + mtk_crtc->cmdq_vblank_cnt = 0;
> > > cmdq_pkt_destroy(data->pkt);
> > > }
> > > #endif
> > > @@ -483,6 +487,15 @@ static void mtk_drm_crtc_update_config(struct mtk_drm_crtc *mtk_crtc,
> > > cmdq_handle->pa_base,
> > > cmdq_handle->cmd_buf_size,
> > > DMA_TO_DEVICE);
> > > + /*
> > > + * CMDQ command should execute in next 3 vblank.
> > > + * One vblank interrupt before send message (occasionally)
> > > + * and one vblank interrupt after cmdq done,
> > > + * so it's timeout after 3 vblank interrupt.
> > > + * If it fail to execute in next 3 vblank, timeout happen.
> > > + */
> > > + mtk_crtc->cmdq_vblank_cnt = 3;
> > > +
> > > mbox_send_message(mtk_crtc->cmdq_client.chan, cmdq_handle);
> > > mbox_client_txdone(mtk_crtc->cmdq_client.chan, 0);
> > > }
> > > @@ -499,11 +512,14 @@ static void mtk_crtc_ddp_irq(void *data)
> > >
> > > #if IS_REACHABLE(CONFIG_MTK_CMDQ)
> > > if (!priv->data->shadow_register && !mtk_crtc->cmdq_client.chan)
> > > + mtk_crtc_ddp_config(crtc, NULL);
> > > + else if (mtk_crtc->cmdq_vblank_cnt > 0 && --mtk_crtc->cmdq_vblank_cnt == 0)
> > I think atomic_dec_and_test() does what you want to do here.
>
> I think this operation is not necessary to be atomic operation, and
> this statement could be reduced to
>
> else if (--mtk_crtc->cmdq_vblank_cnt == 0)

I was thinking about using existing helpers to wrap up the counter
operations, but I agree that it's not necessary.
Just dropping the redundant check would be good enough.


>
> >
> > > + DRM_ERROR("mtk_crtc %d CMDQ execute command timeout!\n",
> > > + drm_crtc_index(&mtk_crtc->base));
> > > #else
> > > if (!priv->data->shadow_register)
> > > -#endif
> > > mtk_crtc_ddp_config(crtc, NULL);
> > > -
> > > +#endif
> > > mtk_drm_finish_page_flip(mtk_crtc);
> > > }
> > >
> > > --
> > > 2.18.0
> > >

2021-11-17 23:51:51

by Chun-Kuang Hu

[permalink] [raw]
Subject: Re: [PATCH v5 3/6] drm/mediatek: Detect CMDQ execution timeout

Hi, Fei:

Fei Shao <[email protected]> 於 2021年10月28日 週四 上午11:19寫道:
>
> Hi Chun-Kuang,
>
> On Thu, Oct 28, 2021 at 7:47 AM Chun-Kuang Hu <[email protected]> wrote:
> >
> > Hi, Fei:
> >
> > Fei Shao <[email protected]> 於 2021年10月27日 週三 下午5:32寫道:
> > >
> > > Hi Jason,
> > >
> > > On Wed, Oct 27, 2021 at 10:19 AM jason-jh.lin <[email protected]> wrote:
> > > >
> > > > From: Chun-Kuang Hu <[email protected]>
> > > >
> > > > CMDQ is used to update display register in vblank period, so
> > > > it should be execute in next 2 vblank. One vblank interrupt
> > > > before send message (occasionally) and one vblank interrupt
> > > > after cmdq done. If it fail to execute in next 3 vblank,
> > > > tiemout happen.
> > > >
> > > > Signed-off-by: Chun-Kuang Hu <[email protected]>
> > > > Signed-off-by: jason-jh.lin <[email protected]>
> > > > Reviewed-by: Chun-Kuang Hu <[email protected]>
> > > > ---
> > > > drivers/gpu/drm/mediatek/mtk_drm_crtc.c | 20 ++++++++++++++++++--
> > > > 1 file changed, 18 insertions(+), 2 deletions(-)
> > > >
> > > > diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> > > > index e23e3224ac67..dad1f85ee315 100644
> > > > --- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> > > > +++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> > > > @@ -54,6 +54,7 @@ struct mtk_drm_crtc {
> > > > #if IS_REACHABLE(CONFIG_MTK_CMDQ)
> > > > struct cmdq_client cmdq_client;
> > > > u32 cmdq_event;
> > > > + u32 cmdq_vblank_cnt;
> > > > #endif
> > > >
> > > > struct device *mmsys_dev;
> > > > @@ -227,7 +228,10 @@ struct mtk_ddp_comp *mtk_drm_ddp_comp_for_plane(struct drm_crtc *crtc,
> > > > static void ddp_cmdq_cb(struct mbox_client *cl, void *mssg)
> > > > {
> > > > struct cmdq_cb_data *data = mssg;
> > > > + struct cmdq_client *cmdq_cl = container_of(cl, struct cmdq_client, client);
> > > > + struct mtk_drm_crtc *mtk_crtc = container_of(cmdq_cl, struct mtk_drm_crtc, cmdq_client);
> > > >
> > > > + mtk_crtc->cmdq_vblank_cnt = 0;
> > > > cmdq_pkt_destroy(data->pkt);
> > > > }
> > > > #endif
> > > > @@ -483,6 +487,15 @@ static void mtk_drm_crtc_update_config(struct mtk_drm_crtc *mtk_crtc,
> > > > cmdq_handle->pa_base,
> > > > cmdq_handle->cmd_buf_size,
> > > > DMA_TO_DEVICE);
> > > > + /*
> > > > + * CMDQ command should execute in next 3 vblank.
> > > > + * One vblank interrupt before send message (occasionally)
> > > > + * and one vblank interrupt after cmdq done,
> > > > + * so it's timeout after 3 vblank interrupt.
> > > > + * If it fail to execute in next 3 vblank, timeout happen.
> > > > + */
> > > > + mtk_crtc->cmdq_vblank_cnt = 3;
> > > > +
> > > > mbox_send_message(mtk_crtc->cmdq_client.chan, cmdq_handle);
> > > > mbox_client_txdone(mtk_crtc->cmdq_client.chan, 0);
> > > > }
> > > > @@ -499,11 +512,14 @@ static void mtk_crtc_ddp_irq(void *data)
> > > >
> > > > #if IS_REACHABLE(CONFIG_MTK_CMDQ)
> > > > if (!priv->data->shadow_register && !mtk_crtc->cmdq_client.chan)
> > > > + mtk_crtc_ddp_config(crtc, NULL);
> > > > + else if (mtk_crtc->cmdq_vblank_cnt > 0 && --mtk_crtc->cmdq_vblank_cnt == 0)
> > > I think atomic_dec_and_test() does what you want to do here.
> >
> > I think this operation is not necessary to be atomic operation, and
> > this statement could be reduced to
> >
> > else if (--mtk_crtc->cmdq_vblank_cnt == 0)
>
> I was thinking about using existing helpers to wrap up the counter
> operations, but I agree that it's not necessary.
> Just dropping the redundant check would be good enough.

I find one thing so that I would like this version. If we do not check
mtk_crtc->cmdq_vblank_cnt > 0, mtk_crtc->cmdq_vblank_cnt would
decrease to minus. And one day it would round to positive. So I would
pick this version instead of v6.

Regards,
Chun-Kuang.

>
>
> >
> > >
> > > > + DRM_ERROR("mtk_crtc %d CMDQ execute command timeout!\n",
> > > > + drm_crtc_index(&mtk_crtc->base));
> > > > #else
> > > > if (!priv->data->shadow_register)
> > > > -#endif
> > > > mtk_crtc_ddp_config(crtc, NULL);
> > > > -
> > > > +#endif
> > > > mtk_drm_finish_page_flip(mtk_crtc);
> > > > }
> > > >
> > > > --
> > > > 2.18.0
> > > >