Hi Enric,
On Thu, May 14, 2020 at 07:35:33PM +0200, Enric Balletbo i Serra wrote:
On 14/5/20 19:12, Enric Balletbo i Serra wrote:
On 14/5/20 18:44, Chun-Kuang Hu wrote:
Enric Balletbo i Serra enric.balletbo@collabora.com 於 2020年5月14日 週四 下午11:42寫道：
On 14/5/20 16:28, Chun-Kuang Hu wrote:
Enric Balletbo Serra eballetbo@gmail.com 於 2020年5月14日 週四 上午12:41寫道：
Missatge de Enric Balletbo i Serra enric.balletbo@collabora.com del dia dv., 1 de maig 2020 a les 17:25: > > Use the drm_bridge_connector helper to create a connector for pipelines > that use drm_bridge. This allows splitting connector operations across > multiple bridges when necessary, instead of having the last bridge in > the chain creating the connector and handling all connector operations > internally. > > Signed-off-by: Enric Balletbo i Serra enric.balletbo@collabora.com > Acked-by: Sam Ravnborg sam@ravnborg.org
A gentle ping on this, I think that this one is the only one that still needs a review in the series.
This is what I reply in patch v3:
Sorry for missing this.
I think the panel is wrapped into next_bridge here,
Yes, you can have for example:
- drm_bridge (mtk_dsi) -> drm_bridge (ps8640 - dsi-to-edp) -> drm_panel_bridge
(edp panel)
or a
- drm_bridge (mtk_dsi)-> drm_panel_bridge (dsi panel)
The _first_ one is my use case
if (panel) {
This handles the second case, where you attach a dsi panel.
dsi->next_bridge = devm_drm_panel_bridge_add(dev, panel);so the next_bridge is a panel_bridge, in its attach function panel_bridge_attach(), according to the flag DRM_BRIDGE_ATTACH_NO_CONNECTOR, if not exist, it would create connector and attach connector to panel.
I'm not sure this flag would exist or not, but for both case, it's strange. If exist, you create connector in this patch but no where to attach connector to panel.
Yes, in fact, this is transitional patch needed, as once I converted mtk_dpi, mtk_dsi and mtk_hdmi to the new drm_bridge API the drm_bridge_connector_init() will be done in mtk_drm_drv. We will need to call drm_bridge_connector_init for dpi and dsi pipes and remove that call from mtk_dsi and mtk_dpi drivers. The graphic controller driver should create connectors and CRTCs, as example you can take a look at drivers/gpu/drm/omapdrm/omap_drv.c
I have such question because I've reviewed omap's driver. In omap's driver, after it call drm_bridge_connector_init(), it does this:
if (pipe->output->panel) { ret = drm_panel_attach(pipe->output->panel, pipe->connector); if (ret < 0) return ret; }
In this patch, you does not do this.
I see, so yes, I am probably missing call drm_panel_attach in case there is a direct panel attached. Thanks for pointing it.
I'll send a new version adding the drm_panel_attach call.
Wait, shouldn't panel be attached on the call of mtk_dsi_bridge_attach as next_bridge points to a bridge or a panel?
static int mtk_dsi_bridge_attach(struct drm_bridge *bridge, enum drm_bridge_attach_flags flags) { struct mtk_dsi *dsi = bridge_to_dsi(bridge);
/* Attach the panel or bridge to the dsi bridge */ return drm_bridge_attach(bridge->encoder, dsi->next_bridge, &dsi->bridge, flags); }
Or I am continuing misunderstanding all this?
Panels should always be wrapped in a drm_bridge, so I think you're doing right. I believe the call to drm_panel_attach() in omapdrm is a leftover that can be removed. I'll have a look at it.
If not exist, the next_brige would create one connector and this brige would create another connector.
I think in your case, mtk_dsi does not directly connect to a panel, so
Exactly
I need a exact explain. Or someone could test this on a directly-connect-panel platform.
I don't think I am breaking this use case but AFAICS there is no users in mainline that directly connect a panel using the mediatek driver. As I said my use case is the other so I can't really test. Do you know anyone that can test this?
I'm not sure who can test this, but [1], which is sent by YT Shen in a series, is a patch to support dsi command mode so dsi could directly connect to panel.
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/dr...
It's better that someone could test this case, but if no one would test this, I could also accept a good-look patch.
> Changes in v4: None > Changes in v3: > - Move the bridge.type line to the patch that adds drm_bridge support. (Laurent Pinchart) > > Changes in v2: None > > drivers/gpu/drm/mediatek/mtk_dsi.c | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c > index 4f3bd095c1ee..471fcafdf348 100644 > --- a/drivers/gpu/drm/mediatek/mtk_dsi.c > +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c > @@ -17,6 +17,7 @@ > > #include <drm/drm_atomic_helper.h> > #include <drm/drm_bridge.h> > +#include <drm/drm_bridge_connector.h> > #include <drm/drm_mipi_dsi.h> > #include <drm/drm_of.h> > #include <drm/drm_panel.h> > @@ -183,6 +184,7 @@ struct mtk_dsi { > struct drm_encoder encoder; > struct drm_bridge bridge; > struct drm_bridge *next_bridge; > + struct drm_connector *connector; > struct phy *phy; > > void __iomem *regs; > @@ -977,10 +979,19 @@ static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi) > */ > dsi->encoder.possible_crtcs = 1; > > - ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL, 0); > + ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL, > + DRM_BRIDGE_ATTACH_NO_CONNECTOR); > if (ret) > goto err_cleanup_encoder; > > + dsi->connector = drm_bridge_connector_init(drm, &dsi->encoder); > + if (IS_ERR(dsi->connector)) { > + DRM_ERROR("Unable to create bridge connector\n"); > + ret = PTR_ERR(dsi->connector); > + goto err_cleanup_encoder; > + } > + drm_connector_attach_encoder(dsi->connector, &dsi->encoder); > + > return 0; > > err_cleanup_encoder: