Re: [PATCH 1/2] drm/mediatek: set panel orientation before drm_dev_register().

From: Hsin-Yi Wang
Date: Tue Apr 20 2021 - 21:57:16 EST


On Wed, Apr 21, 2021 at 7:47 AM Chun-Kuang Hu <chunkuang.hu@xxxxxxxxxx> wrote:
>
> Hi, Hsin-Yi:
>
> Hsin-Yi Wang <hsinyi@xxxxxxxxxxxx> 於 2021年4月20日 週二 下午5:05寫道:
> >
> > On Fri, Apr 9, 2021 at 12:53 PM Hsin-Yi Wang <hsinyi@xxxxxxxxxxxx> wrote:
> > >
> > > drm_dev_register() sets connector->registration_state to
> > > DRM_CONNECTOR_REGISTERED and dev->registered to true. If
> > > drm_connector_set_panel_orientation() is first called after
> > > drm_dev_register(), it will fail several checks and results in following
> > > warning. So set panel orientation in dsi before drm_dev_register() is
> > > called.
>
> All connector would have this problem, so I would like to fix this in
> common code.
> In drm_connector_init(), you could add "panel orientation" property
> with value DRM_MODE_PANEL_ORIENTATION_UNKNOWN, so it would not add new
> object when get modes.

Hi CK,

Calling drm_connector_set_panel_orientation() with
DRM_MODE_PANEL_ORIENTATION_UNKNOWN will be a no-op. And once the
orientation is set, the 2nd call to this is also no-op.
https://elixir.bootlin.com/linux/v5.12-rc8/source/drivers/gpu/drm/drm_connector.c#L2182

The 1st time call to drm_connector_set_panel_orientation() has to be
prior than drm_dev_register().

Orientation is an optional property, and different dsi has different
ways to read and handle this. Eg. vlv_dsi[1], intel_dp[2], so I think
it's better to let each connector decide how to handle orientation.

[1] https://elixir.bootlin.com/linux/v5.12-rc8/source/drivers/gpu/drm/i915/display/vlv_dsi.c#L1632
[2] https://elixir.bootlin.com/linux/v5.12-rc8/source/drivers/gpu/drm/i915/display/intel_dp.c#L6488

Thanks
>
> Regards,
> Chun-Kuang.
>
> > >
> > > [ 4.480976] ------------[ cut here ]------------
> > > [ 4.485603] WARNING: CPU: 5 PID: 369 at drivers/gpu/drm/drm_mode_object.c:45 __drm_mode_object_add+0xb4/0xbc
> > > <snip>
> > > [ 4.609772] Call trace:
> > > [ 4.612208] __drm_mode_object_add+0xb4/0xbc
> > > [ 4.616466] drm_mode_object_add+0x20/0x2c
> > > [ 4.620552] drm_property_create+0xdc/0x174
> > > [ 4.624723] drm_property_create_enum+0x34/0x98
> > > [ 4.629241] drm_connector_set_panel_orientation+0x64/0xa0
> > > [ 4.634716] boe_panel_get_modes+0x88/0xd8
> > > [ 4.638802] drm_panel_get_modes+0x2c/0x48
> > > [ 4.642887] panel_bridge_get_modes+0x1c/0x28
> > > [ 4.647233] drm_bridge_connector_get_modes+0xa0/0xd4
> > > [ 4.652273] drm_helper_probe_single_connector_modes+0x218/0x700
> > > [ 4.658266] drm_mode_getconnector+0x1b4/0x45c
> > > [ 4.662699] drm_ioctl_kernel+0xac/0x128
> > > [ 4.666611] drm_ioctl+0x268/0x410
> > > [ 4.670002] drm_compat_ioctl+0xdc/0xf0
> > > [ 4.673829] __arm64_compat_sys_ioctl+0xc8/0x100
> > > [ 4.678436] el0_svc_common+0xf4/0x1c0
> > > [ 4.682174] do_el0_svc_compat+0x28/0x3c
> > > [ 4.686088] el0_svc_compat+0x10/0x1c
> > > [ 4.689738] el0_sync_compat_handler+0xa8/0xcc
> > > [ 4.694171] el0_sync_compat+0x178/0x180
> > > [ 4.698082] ---[ end trace b4f2db9d9c88610b ]---
> > > [ 4.702721] ------------[ cut here ]------------
> > > [ 4.707329] WARNING: CPU: 5 PID: 369 at drivers/gpu/drm/drm_mode_object.c:243 drm_object_attach_property+0x48/0xb8
> > > <snip>
> > > [ 4.833830] Call trace:
> > > [ 4.836266] drm_object_attach_property+0x48/0xb8
> > > [ 4.840958] drm_connector_set_panel_orientation+0x84/0xa0
> > > [ 4.846432] boe_panel_get_modes+0x88/0xd8
> > > [ 4.850516] drm_panel_get_modes+0x2c/0x48
> > > [ 4.854600] panel_bridge_get_modes+0x1c/0x28
> > > [ 4.858946] drm_bridge_connector_get_modes+0xa0/0xd4
> > > [ 4.863984] drm_helper_probe_single_connector_modes+0x218/0x700
> > > [ 4.869978] drm_mode_getconnector+0x1b4/0x45c
> > > [ 4.874410] drm_ioctl_kernel+0xac/0x128
> > > [ 4.878320] drm_ioctl+0x268/0x410
> > > [ 4.881711] drm_compat_ioctl+0xdc/0xf0
> > > [ 4.885536] __arm64_compat_sys_ioctl+0xc8/0x100
> > > [ 4.890142] el0_svc_common+0xf4/0x1c0
> > > [ 4.893879] do_el0_svc_compat+0x28/0x3c
> > > [ 4.897791] el0_svc_compat+0x10/0x1c
> > > [ 4.901441] el0_sync_compat_handler+0xa8/0xcc
> > > [ 4.905873] el0_sync_compat+0x178/0x180
> > > [ 4.909783] ---[ end trace b4f2db9d9c88610c ]---
> > >
> > > Signed-off-by: Hsin-Yi Wang <hsinyi@xxxxxxxxxxxx>
> >
> > ping on the thread, thanks.
> >
> > > ---
> > > drivers/gpu/drm/mediatek/mtk_dsi.c | 9 +++++++++
> > > 1 file changed, 9 insertions(+)
> > >
> > > diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> > > index ae403c67cbd9..45a702ee09f3 100644
> > > --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> > > +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> > > @@ -205,6 +205,7 @@ struct mtk_dsi {
> > > u32 irq_data;
> > > wait_queue_head_t irq_wait_queue;
> > > const struct mtk_dsi_driver_data *driver_data;
> > > + enum drm_panel_orientation orientation;
> > > };
> > >
> > > static inline struct mtk_dsi *bridge_to_dsi(struct drm_bridge *b)
> > > @@ -966,6 +967,8 @@ static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi)
> > > }
> > > drm_connector_attach_encoder(dsi->connector, &dsi->encoder);
> > >
> > > + drm_connector_set_panel_orientation(dsi->connector, dsi->orientation);
> > > +
> > > return 0;
> > >
> > > err_cleanup_encoder:
> > > @@ -1029,6 +1032,12 @@ static int mtk_dsi_probe(struct platform_device *pdev)
> > > ret = PTR_ERR(dsi->next_bridge);
> > > goto err_unregister_host;
> > > }
> > > +
> > > + ret = of_drm_get_panel_orientation(panel->dev->of_node, &dsi->orientation);
> > > + if (ret) {
> > > + dev_err(dev, "failed to get panel orientation %d\n", ret);
> > > + return ret;
> > > + }
> > > }
> > >
> > > dsi->driver_data = of_device_get_match_data(dev);
> > > --
> > > 2.31.1.295.g9ea45b61b8-goog
> > >