Re: [PATCH v9 5/5] drm/bridge/synopsys: dw-hdmi: Add missing bridge detach

[JeffyChen]

Hi Laurent,

On 03/03/2018 05:49 AM, Laurent Pinchart wrote:
> Hi Enric,
>
> Thank you for the patch.
>
> On Friday, 2 March 2018 19:57:57 EET Enric Balletbo i Serra wrote:
> > From: Jeffy Chen <jeffy.chen@xxxxxxxxxxxxxx>
> >
> > We inited connector in attach(), so need a detach() to cleanup.
>
> Do we ? The dw-hdmi driver already sets drm_connector_cleanup() as the
> connector .destroy() handler, and the .destroy() operation is called by the
> DRM core. None of the other bridge drivers call drm_connector_cleanup()
> directly.

hmmm, checking the code, there are also lots of drivers do the 
cleanup(drm_connector_cleanup or funcs->destroy):
drm# grep -r "connector.*funcs->destroy" .
./rockchip/inno_hdmi.c: hdmi->connector.funcs->destroy(&hdmi->connector);
./rockchip/cdn-dp-core.c:       connector->funcs->destroy(connector);
./bridge/analogix/analogix_dp_core.c: 
dp->connector.funcs->destroy(&dp->connector);
./msm/hdmi/hdmi.c: 
hdmi->connector->funcs->destroy(hdmi->connector);
./msm/dsi/dsi.c: 
msm_dsi->connector->funcs->destroy(msm_dsi->connector);
./msm/edp/edp.c: 
edp->connector->funcs->destroy(edp->connector);
./zte/zx_hdmi.c:        hdmi->connector.funcs->destroy(&hdmi->connector);
./drm_connector.c:      connector->funcs->destroy(connector);
./drm_connector.c:              connector->funcs->destroy(connector);
./nouveau/dispnv04/disp.c: 
connector->funcs->destroy(connector);
./nouveau/nv50_display.c: 
mstc->connector.funcs->destroy(&mstc->connector);
./nouveau/nv50_display.c: 
connector->funcs->destroy(connector);



when i debug analogix_dp bind/unbind, i found that we need to cleanup 
the connector(reported by kmemleak). so i added it to 
./bridge/analogix/analogix_dp_core.c...after that i saw dw-hdmi missing 
that too(by checking the code), so make this patch.

but i didn't really tested it on devices using dw-hdmi, so i'm not very 
sure the dw-hdmi(maybe also other bridges) is the same with analogix_dp.

i can try to find a chromebook veyron to check it next week :)

but even there's a leak, i'm still not very sure about:
should the caller of drm_connector_init cleanup it
or the caller of drm_bridge_attach should do it(for example 
analogix_dp_bind/analogix_dp_unbind)
or should the DRM core take care of that?

> > Signed-off-by: Jeffy Chen <jeffy.chen@xxxxxxxxxxxxxx>
> > Signed-off-by: Thierry Escande <thierry.escande@xxxxxxxxxxxxx>
> > Signed-off-by: Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx>
> > ---
> >
> > Changes in v9: None
> >
> >   drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 8 ++++++++
> >   1 file changed, 8 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> > b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c index
> > f9802399cc0d..5626922f95f9 100644
> > --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> > +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> > @@ -1985,6 +1985,13 @@ static int dw_hdmi_bridge_attach(struct drm_bridge
> > *bridge) return 0;
> >   }
> >
> > +static void dw_hdmi_bridge_detach(struct drm_bridge *bridge)
> > +{
> > +	struct dw_hdmi *hdmi = bridge->driver_private;
> > +
> > +	drm_connector_cleanup(&hdmi->connector);
> > +}
> > +
> >   static enum drm_mode_status
> >   dw_hdmi_bridge_mode_valid(struct drm_bridge *bridge,
> >   			  const struct drm_display_mode *mode)
> > @@ -2041,6 +2048,7 @@ static void dw_hdmi_bridge_enable(struct drm_bridge
> > *bridge)
> >
> >   static const struct drm_bridge_funcs dw_hdmi_bridge_funcs = {
> >   	.attach = dw_hdmi_bridge_attach,
> > +	.detach = dw_hdmi_bridge_detach,
> >   	.enable = dw_hdmi_bridge_enable,
> >   	.disable = dw_hdmi_bridge_disable,
> >   	.mode_set = dw_hdmi_bridge_mode_set,