Re: [PATCH v8 22/23] drm/mediatek: Power on devices in OVL adaptor when atomic enable

From: "Shawn Sung (宋孝謙)" <Shawn.Sung@mediatek.com>
To: "CK Hu (胡俊光)" <ck.hu@mediatek.com>,
	"matthias.bgg@gmail.com" <matthias.bgg@gmail.com>,
	"angelogioacchino.delregno@collabora.com"
	<angelogioacchino.delregno@collabora.com>,
	"robh+dt@kernel.org" <robh+dt@kernel.org>,
	"krzysztof.kozlowski+dt@linaro.org"
	<krzysztof.kozlowski+dt@linaro.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-mediatek@lists.infradead.org"
	<linux-mediatek@lists.infradead.org>,
	"Yongqiang Niu (牛永强)" <yongqiang.niu@mediatek.com>,
	"chunkuang.hu@kernel.org" <chunkuang.hu@kernel.org>,
	"Jason-JH Lin (林睿祥)" <Jason-JH.Lin@mediatek.com>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"Moudy Ho (何宗原)" <Moudy.Ho@mediatek.com>,
	"Nancy Lin (林欣螢)" <Nancy.Lin@mediatek.com>,
	"daniel@ffwll.ch" <daniel@ffwll.ch>,
	"p.zabel@pengutronix.de" <p.zabel@pengutronix.de>,
	"mchehab@kernel.org" <mchehab@kernel.org>,
	"dri-devel@lists.freedesktop.org"
	<dri-devel@lists.freedesktop.org>,
	"Nathan Lu (呂東霖)" <Nathan.Lu@mediatek.com>,
	"airlied@gmail.com" <airlied@gmail.com>,
	"sean@poorly.run" <sean@poorly.run>,
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	"johnson.wang@mediatek.corp-partner.google.com"
	<johnson.wang@mediatek.corp-partner.google.com>
Subject: Re: [PATCH v8 22/23] drm/mediatek: Power on devices in OVL adaptor when atomic enable
Date: Wed, 18 Oct 2023 04:54:31 +0000	[thread overview]
Message-ID: <691c1458eb5e45d8c14f24e78f47b2840f589ea7.camel@mediatek.com> (raw)
In-Reply-To: <c8e94835fcba4692d34eb002ef4c14f554c50b0b.camel@mediatek.com>

Hi CK,

On Wed, 2023-10-18 at 02:02 +0000, CK Hu (胡俊光) wrote:
> Hi, Hsiao-chien:
> 
> On Mon, 2023-10-16 at 18:40 +0800, Hsiao Chien Sung wrote:
> > Different from OVL, OVL adaptor is a pseudo device so we didn't
> > define it in the device tree, consequently,
> > pm_runtime_resume_and_get()
> > called by .atomic_enable() powers on no device in OVL adaptor and
> > leads to power outage in the corresponding IOMMU.
> > 
... snip ...
> > +int mtk_ovl_adaptor_power_on(struct device *dev)
> > +{
> > +	int i, ret;
> > +	struct mtk_disp_ovl_adaptor *ovl_adaptor =
> > dev_get_drvdata(dev);
> > +
> > +	for (i = 0; i < OVL_ADAPTOR_ID_MAX; i++) {
> > +		if (!ovl_adaptor->ovl_adaptor_comp[i] ||
> > +		    !comp_matches[i].funcs->power_on)
> > +			continue;
> 
> To simplify the code, you could call mtk_ddp_comp_power_on() for all
> sub device, and drop power_on()/power_off() of mdp_rdma.
> 
> Regards,
> CK
> 

Since ovl_adaptor_comp is a `struct device`, we can't reuse
mtk_ddp_comp_power_on() here. Had submited a new version (v9) and wrap
the power off procedure as a static inline function to reuse it.

Regards,
Shawn

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