linux-kernel - Re: [PATCH v3] drm/mediatek: Move mtk_crtc_finish_page_flip() to ddp_cmdq

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Message-ID: <c3935ca3e990f6f608326cef1dd495d5913c227d.camel@mediatek.com>
Date: Wed, 11 Dec 2024 03:27:59 +0000
From: Jason-JH Lin (林睿祥) <Jason-JH.Lin@...iatek.com>
To: CK Hu (胡俊光) <ck.hu@...iatek.com>,
	"chunkuang.hu@...nel.org" <chunkuang.hu@...nel.org>, "AngeloGioacchino Del
 Regno" <angelogioacchino.delregno@...labora.com>
CC: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Singo Chang (張興國) <Singo.Chang@...iatek.com>,
	"linux-mediatek@...ts.infradead.org" <linux-mediatek@...ts.infradead.org>,
	Shawn Sung (宋孝謙) <Shawn.Sung@...iatek.com>,
	Nancy Lin (林欣螢) <Nancy.Lin@...iatek.com>,
	"dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
	Project_Global_Chrome_Upstream_Group
	<Project_Global_Chrome_Upstream_Group@...iatek.com>,
	"linux-arm-kernel@...ts.infradead.org" <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v3] drm/mediatek: Move mtk_crtc_finish_page_flip() to
 ddp_cmdq_cb()

Hi CK,

[snip]

> > @@ -109,9 +109,14 @@ 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);
> >  
> > +	if (!priv->data->shadow_register)
> > +		return;
> > +
> 
> I forget one case.
> For the CPU case (SoC has no shadow register and CONFIG_MTK_CMDQ is
> not enable),
> this driver should still work.
> CPU case is not a usual case, but it could be used in some
> verification case.
> So the condition may be
> 
> #if IS_REACHABLE(CONFIG_MTK_CMDQ)
> 	if (mtk_crtc->cmdq_client.chan)
> 		return;
> #endif
> 

OK, I'll change the condition like this.

> >  	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);

[snip]

> > @@ -584,6 +592,10 @@ static void mtk_crtc_update_config(struct
> > mtk_crtc *mtk_crtc, bool needs_vblank)
> >  		mtk_mutex_acquire(mtk_crtc->mutex);
> >  		mtk_crtc_ddp_config(crtc, NULL);
> >  		mtk_mutex_release(mtk_crtc->mutex);
> > +
> > +		spin_lock_irqsave(&mtk_crtc->config_lock, flags);
> > +		mtk_crtc->config_updating = false;
> > +		spin_unlock_irqrestore(&mtk_crtc->config_lock, flags);
> >  	}
> >  #if IS_REACHABLE(CONFIG_MTK_CMDQ)
> >  	if (mtk_crtc->cmdq_client.chan) {
> > @@ -606,13 +618,14 @@ static void mtk_crtc_update_config(struct
> > mtk_crtc *mtk_crtc, bool needs_vblank)
> >  		 */
> >  		mtk_crtc->cmdq_vblank_cnt = 3;
> >  
> > +		spin_lock_irqsave(&mtk_crtc->config_lock, flags);
> > +		mtk_crtc->config_updating = false;
> > +		spin_unlock_irqrestore(&mtk_crtc->config_lock, flags);
> > +
> >  		mbox_send_message(mtk_crtc->cmdq_client.chan,
> > cmdq_handle);
> >  		mbox_client_txdone(mtk_crtc->cmdq_client.chan, 0);
> >  	}
> >  #endif
> > -	spin_lock_irqsave(&mtk_crtc->config_lock, flags);
> > -	mtk_crtc->config_updating = false;
> > -	spin_unlock_irqrestore(&mtk_crtc->config_lock, flags);
> 
> For the CPU case (SoC has no shadow register and CONFIG_MTK_CMDQ is
> not enable),
> This code is necessary.
> Maybe keep these code or some modification for CPU case.
> 

OK, I'll keep the original flow and only modify for
IS_REACHABLE(CONFIG_MTK_CMDQ) case.

Regards,
Jason-JH.lin

> Regards,
> CK