On Thu, Oct 7, 2021 at 6:24 PM Stephen Boyd <swboyd@xxxxxxxxxxxx> wrote: > > Quoting Saravana Kannan (2021-10-07 18:10:24) > > On Thu, Oct 7, 2021 at 1:11 PM Stephen Boyd <swboyd@xxxxxxxxxxxx> wrote: > > > > > > Quoting Stephen Boyd (2021-10-07 11:40:07) > > > > Quoting Saravana Kannan (2021-10-06 20:07:11) > > > > > On Wed, Oct 6, 2021 at 12:38 PM Stephen Boyd <swboyd@xxxxxxxxxxxx> wrote: > > > > > > diff --git a/drivers/base/component.c b/drivers/base/component.c > > > > > > index 0a41bbe14981..d99e99cabb99 100644 > > > > > > --- a/drivers/base/component.c > > > > > > +++ b/drivers/base/component.c > > > > [...] > > > > > > + continue; > > > > > > + > > > > > > + /* Matches put in component_del() */ > > > > > > + get_device(&adev->dev); > > > > > > + c->link = device_link_add(&adev->dev, c->dev, > > > > > > + DL_FLAG_STATELESS | DL_FLAG_PM_RUNTIME); > > > > > > > > > > Remove the STATELESS flag and you'll get a bunch of other stuff done for free: > > > > > > > > I tried that and it didn't work for me. The aggregate device never > > > > probed and I was left with no display. Let me see if I can reproduce it > > > > with logging to provide more details. > > > > > > This patch fixes it (whitespace damaged sorry). > > > > Not sure why you have to trigger an explicit rescan, but instead of > > this patch below, you could also try setting this flag instead? > > DL_FLAG_AUTOPROBE_CONSUMER > > > > I'd rather not conflate component driver probe with component_add() > being called. It's simpler if that is the case, i.e. all component > drivers are calling component_add() in their driver probe routine, but I > don't know if that's always true. I did this poor audit of the kernel > > $ git grep -p \[^_]component_add | grep \.c= | grep -v probe > drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c=static int > amdgpu_dm_audio_init(struct amdgpu_device *adev) > drivers/gpu/drm/i915/display/intel_audio.c=static void > i915_audio_component_init(struct drm_i915_private *dev_priv) > drivers/gpu/drm/i915/display/intel_hdcp.c=void > intel_hdcp_component_init(struct drm_i915_private *dev_priv) > drivers/gpu/drm/nouveau/dispnv50/disp.c=nv50_audio_component_init(struct > nouveau_drm *drm) > drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c=static int > dw_mipi_dsi_rockchip_host_attach(void *priv_data, > drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c=static int > dw_mipi_dsi_dphy_init(struct phy *phy) > drivers/gpu/drm/vc4/vc4_dsi.c=static int vc4_dsi_host_attach(struct > mipi_dsi_host *host, > > and then peeking at rockchip above I see that component_add() is called > in the mipi dsi attach ops and then I got lost trying to figure out > where it ends up. Maybe it is still in some probe call? > > Anyway, I think we still have to do a rescan so that we can try to bind > the aggregate device. Is there a better API to use for that? If you know the exact device, you could call device_attach()? That's what bus_rescan_devices() eventually calls, but you skip the unnecessary looping over all the other devices. -Saravana
