On 27.08.2019 22:03, John Stultz wrote: > On Mon, Aug 19, 2019 at 3:27 PM John Stultz <john.stultz@xxxxxxxxxx> wrote: >> On Thu, Jun 27, 2019 at 8:18 AM Matt Redfearn <matt.redfearn@xxxxxxxxxx> wrote: >>> In contrast to all of the DSI panel drivers in drivers/gpu/drm/panel >>> which attach to the DSI host via mipi_dsi_attach() at probe time, the >>> ADV7533 bridge device does not. Instead it defers this to the point that >>> the upstream device connects to its bridge via drm_bridge_attach(). >>> The generic Synopsys MIPI DSI host driver does not register it's own >>> drm_bridge until the MIPI DSI has attached. But it does not call >>> drm_bridge_attach() on the downstream device until the upstream device >>> has attached. This leads to a chicken and the egg failure and the DRM >>> pipeline does not complete. >>> Since all other mipi_dsi_device drivers call mipi_dsi_attach() in >>> probe(), make the adv7533 mipi_dsi_device do the same. This ensures that >>> the Synopsys MIPI DSI host registers it's bridge such that it is >>> available for the upstream device to connect to. >>> >>> Signed-off-by: Matt Redfearn <matt.redfearn@xxxxxxxxxx> >>> >>> --- >> As a heads up, I just did some testing on drm-misc-next and this patch >> seems to be breaking the HiKey board. On bootup, I'm seeing: >> [ 4.209615] adv7511 2-0039: 2-0039 supply avdd not found, using >> dummy regulator >> [ 4.217075] adv7511 2-0039: 2-0039 supply dvdd not found, using >> dummy regulator >> [ 4.224453] adv7511 2-0039: 2-0039 supply pvdd not found, using >> dummy regulator >> [ 4.231804] adv7511 2-0039: 2-0039 supply a2vdd not found, using >> dummy regulator >> [ 4.239242] adv7511 2-0039: 2-0039 supply v3p3 not found, using >> dummy regulator >> [ 4.246615] adv7511 2-0039: 2-0039 supply v1p2 not found, using >> dummy regulator >> [ 4.272970] adv7511 2-0039: failed to find dsi host >> >> over and over. The dummy regulator messages are normal, but usually >> [ 4.444315] kirin-drm f4100000.ade: bound f4107800.dsi (ops dsi_ops) >> >> Starts up right afterward. > Hey Matt, Andrzej, > I just wanted to follow up on this as this patch is breaking a > couple of boards. Any sense of what might be missing, or is this > something we should revert? > > I'm happy to test any patch ideas you have. I guess this is circular dependency issue: - adv waits for dsi-host, then it creates drm_bridge, - dsi-driver waits for drm_bridge, then it creates dsi host. The patch introduces proper order: - 1st we should register devices buses, - then we should wait for drm components. So the best solution would be to fix f4107800.dsi driver - it shouldn't look for drm_bridge in probe, instead it should register dsi_host, and in dsi host attach callback look for drm_bridge, then call component_add (if all required resources are gathered), see dw_mipi_dsi_rockchip_host_attach for example. Regards Andrzej > > thanks > -john > > _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
