linux-kernel - Re: [PATCH v13 06/10] drm/mediatek: Add MT8195 External DisplayPort support

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Date:   Tue, 5 Jul 2022 17:51:54 +0800
From:   Rex-BC Chen <rex-bc.chen@...iatek.com>
To:     AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>,
        "chunkuang.hu@...nel.org" <chunkuang.hu@...nel.org>,
        "p.zabel@...gutronix.de" <p.zabel@...gutronix.de>,
        "daniel@...ll.ch" <daniel@...ll.ch>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "krzysztof.kozlowski+dt@...aro.org" 
        <krzysztof.kozlowski+dt@...aro.org>,
        "mripard@...nel.org" <mripard@...nel.org>,
        "tzimmermann@...e.de" <tzimmermann@...e.de>,
        "matthias.bgg@...il.com" <matthias.bgg@...il.com>,
        "deller@....de" <deller@....de>,
        "airlied@...ux.ie" <airlied@...ux.ie>
CC:     "msp@...libre.com" <msp@...libre.com>,
        "granquet@...libre.com" <granquet@...libre.com>,
        Jitao Shi (石记涛) 
        <jitao.shi@...iatek.com>,
        "wenst@...omium.org" <wenst@...omium.org>,
        CK Hu (胡俊光) 
        <ck.hu@...iatek.com>,
        "LiangXu Xu (徐亮)" 
        <LiangXu.Xu@...iatek.com>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        "linux-mediatek@...ts.infradead.org" 
        <linux-mediatek@...ts.infradead.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-fbdev@...r.kernel.org" <linux-fbdev@...r.kernel.org>,
        Project_Global_Chrome_Upstream_Group 
        <Project_Global_Chrome_Upstream_Group@...iatek.com>
Subject: Re: [PATCH v13 06/10] drm/mediatek: Add MT8195 External DisplayPort
 support

On Fri, 2022-07-01 at 16:14 +0800, AngeloGioacchino Del Regno wrote:
> Il 01/07/22 08:28, Bo-Chen Chen ha scritto:
> > From: Guillaume Ranquet <granquet@...libre.com>
> > 
> > This patch adds External DisplayPort support to the mt8195 eDP
> > driver.
> > 
> > Signed-off-by: Guillaume Ranquet <granquet@...libre.com>
> > Signed-off-by: Bo-Chen Chen <rex-bc.chen@...iatek.com>
> > ---
> >   drivers/gpu/drm/mediatek/mtk_dp.c     | 197
> > +++++++++++++++++++++-----
> >   drivers/gpu/drm/mediatek/mtk_dp_reg.h |   1 +
> >   2 files changed, 161 insertions(+), 37 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c
> > b/drivers/gpu/drm/mediatek/mtk_dp.c
> > index b672d5a6f5bd..c3be97dd055c 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_dp.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_dp.c
> > @@ -105,6 +105,7 @@ struct mtk_dp {
> >   	struct regmap *regs;
> >   
> >   	bool enabled;
> > +	bool has_fec;
> 
> You're introducing this has_fec variable here....
> 
> >   
> >   	struct drm_connector *conn;
> >   };
> 
> 
> > @@ -1018,6 +1074,8 @@ static void
> > mtk_dp_initialize_priv_data(struct mtk_dp *mtk_dp)
> >   	mtk_dp->info.depth = DP_MSA_MISC_8_BPC;
> >   	memset(&mtk_dp->info.timings, 0, sizeof(struct
> > mtk_dp_timings));
> >   	mtk_dp->info.timings.frame_rate = 60;
> > +
> > +	mtk_dp->has_fec = false;
> 
> .... setting it as false here ....
> 
> >   }
> >   
> >   static void mtk_dp_setup_tu(struct mtk_dp *mtk_dp)
> > @@ -1498,15 +1562,38 @@ static int mtk_dp_init_port(struct mtk_dp
> > *mtk_dp)
> >   static irqreturn_t mtk_dp_hpd_event_thread(int hpd, void *dev)
> >   {
> >   	struct mtk_dp *mtk_dp = dev;
> > +	int event;
> >   	u8 buf[DP_RECEIVER_CAP_SIZE] = {};
> >   
> > +	event = mtk_dp_plug_state(mtk_dp) ?
> > +		connector_status_connected :
> > connector_status_disconnected;
> > +
> > +	if (event < 0)
> > +		return IRQ_HANDLED;
> > +
> > +	dev_info(mtk_dp->dev, "drm_helper_hpd_irq_event\n");
> 
> P.S.: This should be a dev_dbg().
> 
> > +	drm_helper_hpd_irq_event(mtk_dp->bridge.dev);
> > +
> >   	if (mtk_dp->train_info.cable_state_change) {
> >   		mtk_dp->train_info.cable_state_change = false;
> >   
> > -		mtk_dp_update_bits(mtk_dp, MTK_DP_TOP_PWR_STATE,
> > -				   DP_PWR_STATE_BANDGAP_TPLL_LANE,
> > -				   DP_PWR_STATE_MASK);
> > -		drm_dp_read_dpcd_caps(&mtk_dp->aux, buf);
> > +		if (!mtk_dp->train_info.cable_plugged_in) {
> > +			mtk_dp_video_mute(mtk_dp, true);
> > +
> > +			mtk_dp_initialize_priv_data(mtk_dp);
> > +			mtk_dp_set_idle_pattern(mtk_dp, true);
> > +			if (mtk_dp->has_fec)
> 
> ...and you're checking it here, but there's nothing ever setting that
> as true!
> 
> Is there anything you forgot? :-)
> 
> Cheers,
> Angelo

Hello Angelo,

Thanks for your review.
We do not support fec currently, so I will drop them.

Thanks!

BRs,
Bo-Chen