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Message-ID: <d26f894c12ae21a64dcf5926ebf0fc1cffbb39d5.camel@mediatek.com>
Date: Tue, 23 Dec 2025 06:34:33 +0000
From: LIANKUN YANG (杨连坤) <Liankun.Yang@...iatek.com>
To: Peng Liu (刘鹏) <Peng.Liu@...iatek.com>,
Mac Shen (沈俊) <Mac.Shen@...iatek.com>,
"chunkuang.hu@...nel.org" <chunkuang.hu@...nel.org>, "simona@...ll.ch"
<simona@...ll.ch>, "p.zabel@...gutronix.de" <p.zabel@...gutronix.de>,
CK Hu (胡俊光) <ck.hu@...iatek.com>,
Project_Global_Chrome_Upstream_Group
<Project_Global_Chrome_Upstream_Group@...iatek.com>, "airlied@...il.com"
<airlied@...il.com>, "matthias.bgg@...il.com" <matthias.bgg@...il.com>,
AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
CC: "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>, "linux-mediatek@...ts.infradead.org"
<linux-mediatek@...ts.infradead.org>, "linux-kernel@...r.kernel.org"
<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v7 2/2] drm/mediatek: Add isolation to edp
On Wed, 2025-12-17 at 10:08 +0000, CK Hu (胡俊光) wrote:
> On Tue, 2025-11-04 at 16:55 +0800, Liankun Yang wrote:
> > Because edp doesn't expect any (un)plug events during runtime and
> > its process differs from DP. Therefore, it is necessary to isolate
> > the parsing capability, panel power, training state and enable
> > state.
> >
> > And DP related behaviors are adjusted to execute in the second half
> > of the interrupt.
> > For DP details, see drm/mediatek: Adjust bandwidth limit for DP
> >
> > Signed-off-by: Liankun Yang <liankun.yang@...iatek.com>
> > ---
> > drivers/gpu/drm/mediatek/mtk_dp.c | 37 +++++++++++++++----------
> > ------
> > 1 file changed, 18 insertions(+), 19 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c
> > b/drivers/gpu/drm/mediatek/mtk_dp.c
> > index 0ba2c208811c..efd4c45985ca 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_dp.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_dp.c
> > @@ -2187,7 +2187,8 @@ static const struct drm_edid
> > *mtk_dp_edid_read(struct drm_bridge *bridge,
> > * Parse capability here to let atomic_get_input_bus_fmts and
> > * mode_valid use the capability to calculate sink bitrates.
> > */
> > - if (mtk_dp_parse_capabilities(mtk_dp)) {
> > + if (mtk_dp->bridge.type == DRM_MODE_CONNECTOR_eDP &&
> > + mtk_dp_parse_capabilities(mtk_dp)) {
>
> This is not related to dp training.
> If dp does not need to parse edid, describe WHY and do not mix edid
> modification with dp training modification.
>
`mtk_dp_parse_capabilities` is related to DP training, it is
used in `mtk_dp_hpd_event_thread` before DP training, and then only
used by eDP when read edid.
Read edid continued according to its original logic and was unaffected.
...
drm_edid = drm_edid_read_ddc(connector, &mtk_dp->aux.ddc);
/*
* Parse capability here to let atomic_get_input_bus_fmts and
* mode_valid use the capability to calculate sink bitrates.
*/
if (mtk_dp_parse_capabilities(mtk_dp)) {
drm_err(mtk_dp->drm_dev, "Can't parse capabilities\n");
drm_edid_free(drm_edid);
drm_edid = NULL;
}
if (drm_edid) {
...
> > drm_err(mtk_dp->drm_dev, "Can't parse capabilities\n");
> > drm_edid_free(drm_edid);
> > drm_edid = NULL;
> > @@ -2385,13 +2386,15 @@ static void
> > mtk_dp_bridge_atomic_enable(struct drm_bridge *bridge,
> > return;
> > }
> >
> > - mtk_dp_aux_panel_poweron(mtk_dp, true);
> > + if (mtk_dp->data->bridge_type == DRM_MODE_CONNECTOR_eDP) {
> > + mtk_dp_aux_panel_poweron(mtk_dp, true);
> >
> > - /* Training */
> > - ret = mtk_dp_training(mtk_dp);
> > - if (ret) {
> > - drm_err(mtk_dp->drm_dev, "Training failed, %d\n", ret);
> > - goto power_off_aux;
> > + /* Training */
> > + ret = mtk_dp_training(mtk_dp);
> > + if (ret) {
> > + drm_err(mtk_dp->drm_dev, "Training failed,
> > %d\n", ret);
> > + goto power_off_aux;
> > + }
>
> Merge this to previous patch.
>
> > }
> >
> > ret = mtk_dp_video_config(mtk_dp);
> > @@ -2411,7 +2414,9 @@ static void
> > mtk_dp_bridge_atomic_enable(struct drm_bridge *bridge,
> > sizeof(mtk_dp->info.audio_cur_cfg));
> > }
> >
> > - mtk_dp->enabled = true;
> > + if (mtk_dp->data->bridge_type == DRM_MODE_CONNECTOR_eDP)
> > + mtk_dp->enabled = true;
>
> Merge this to previous patch.
>
> > +
> > mtk_dp_update_plugged_status(mtk_dp);
> >
> > return;
> > @@ -2426,21 +2431,15 @@ static void
> > mtk_dp_bridge_atomic_disable(struct drm_bridge *bridge,
> > {
> > struct mtk_dp *mtk_dp = mtk_dp_from_bridge(bridge);
> >
> > - mtk_dp->enabled = false;
> > + if (mtk_dp->data->bridge_type == DRM_MODE_CONNECTOR_eDP) {
> > + mtk_dp->enabled = false;
>
> Merge this to previous patch.
>
> > + mtk_dp_aux_panel_poweron(mtk_dp, false);
>
> You change the code flow of DRM_MODE_CONNECTOR_eDP.
> I think you should not change this.
>
> > + }
> > +
> > mtk_dp_update_plugged_status(mtk_dp);
> > mtk_dp_video_enable(mtk_dp, false);
> > mtk_dp_audio_mute(mtk_dp, true);
> >
> > - if (mtk_dp->train_info.cable_plugged_in) {
> > - drm_dp_dpcd_writeb(&mtk_dp->aux, DP_SET_POWER,
> > DP_SET_POWER_D3);
> > - usleep_range(2000, 3000);
>
> For DRM_MODE_CONNECTOR_DP, you remove this usleep. This may cause
> side effect.
> Doesn't it?
>
The modification to `mtk_dp_bridge_atomic_disable` here is base on
the same logic as `mtk_dp_aux_panel_poweron(mtk_dp, false);`.
Modify part of in `mtk_dp_bridge_atomic_disable`
if (mtk_dp->train_info.cable_plugged_in) {
drm_dp_dpcd_writeb(&mtk_dp->aux, DP_SET_POWER, DP_SET_POWER_D3);
usleep_range(2000, 3000);
}
/* power off aux */
mtk_dp_update_bits(mtk_dp, MTK_DP_TOP_PWR_STATE,
DP_PWR_STATE_BANDGAP_TPLL,
DP_PWR_STATE_MASK);
Modify part of in `mtk_dp_aux_panel_poweron(mtk_dp, false);`
if (pwron) {
....
} else {
/* power off panel */
drm_dp_dpcd_writeb(&mtk_dp->aux, DP_SET_POWER, DP_SET_POWER_D3);
usleep_range(2000, 3000);
/* power off aux */
mtk_dp_update_bits(mtk_dp, MTK_DP_TOP_PWR_STATE,
DP_PWR_STATE_BANDGAP_TPLL,
DP_PWR_STATE_MASK);
}
The `mtk_dp_aux_panel_poweron` function fails to align.
Within the `mtk_dp_hpd_event_thread`, if DP is disconnected,
the `mtk_dp_aux_panel_poweron` function will write from `aux`
to `DPRX`, causing a failure and thus preventing symmetry.
> > - }
> > -
> > - /* power off aux */
> > - mtk_dp_update_bits(mtk_dp, MTK_DP_TOP_PWR_STATE,
> > - DP_PWR_STATE_BANDGAP_TPLL,
> > - DP_PWR_STATE_MASK);
>
> if (mtk_dp->data->bridge_type == DRM_MODE_CONNECTOR_eDP) {
> /* power off aux */
> mtk_dp_update_bits(mtk_dp, MTK_DP_TOP_PWR_STATE,
> DP_PWR_STATE_BANDGAP_TPLL,
> DP_PWR_STATE_MASK);
> }
>
> Regards,
> CK
>
> > -
> > /* SDP path reset sw*/
> > mtk_dp_sdp_path_reset(mtk_dp);
> >
>
>
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