On 31.08.2018 10:56, Linus Walleij wrote: > On Thu, Aug 30, 2018 at 4:41 PM Andrzej Hajda <a.hajda@xxxxxxxxxxx> wrote: >> [Me] >>> This happens because the connector struct device is the >>> same as the bridge struct device, I suppose. >> I guess it is rather because the code tries to make circular dependency: >> 1. panel depends on dsi-host because it is MIPI-DSI child device. >> 2. dsi-host probably depends on drm parent device (connector->dev->dev) >> - what drm driver do you use? > The driver is added in this patch, it's at this uncomfortable stage > where I have to make a big upfront design for a new DRM driver > and everything is shaky and unreviewed. > > So to get it out for proper review it needs to be working and to > get it working I need review :D DRM development catch 22. > > But here is the patch adding it all, in some in-flight state: > https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-stericsson.git/commit/?h=ux500-mcde > > Thanks a lot for these notes, I hope I can figure it out! > >> 3. drm parent dev depends on panel: this patch adds this dependency. >> >> If 2nd point is true it becomes circular dependency, but please verify it. > I tried to not make the DRM parent dev depend on the panel. > > AFAICT (1) is true, (2) is true but not (3). See code of drm_panel_attach after subject patch [1]: panel->link = device_link_add(connector->dev->dev, panel->dev, 0); It is quite clear that connector->dev->dev is 'drm_device parent device' so you have drm-parent depends on panel->dev. IMO this is incorrect dependency, and the cause of error, it is not drm_device parent who depends on the panel, but drm_device itself. [1]: https://elixir.bootlin.com/linux/v4.19-rc1/source/drivers/gpu/drm/drm_panel.c#L108 Regards Andrzej > > Yours, > Linus Walleij > > _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
