> Am 10.11.2020 um 14:49 schrieb H. Nikolaus Schaller <hns@xxxxxxxxxxxxx>: > > Hi Tomi, > >> Am 09.11.2020 um 12:33 schrieb Tomi Valkeinen <tomi.valkeinen@xxxxxx>: >> >> On 09/11/2020 13:09, H. Nikolaus Schaller wrote: >> >>>>> I see. >>>>> Anyways there is missing some simple thing which makes the driver not prepared/enabled. >>>>> Or is this related to VC? >>>> >>>> No, that's not related to the VC. >>> >>> Ok, then it is worth searching for that independently. Any idea/hint what could be missing? >> >> Well, if I had to guess, I would go for either 1) some registration or such is missing from the >> panel driver, or 2) some config value is invalid, which makes the DRM framework or the DSI driver >> fail before calling prepare or enable. > > I did now some tests based on v5.10-rc3 by adding mre and more printk() and dump_stack(). > And I did blacklist the panel driver so that I could boot and after modprobing it manually > I could trigger a re-probe by inserting some USB memory stick. > > With this procedure I could trace the problem down to this call sequence: > > dsi_probe() > ... > w677l_probe() > drm_panel_add() -- after this, of_drm_find_panel() is successful > ... > component_add() > try_to_bring_up_master() > master->ops->bind(master->dev) > > This call to bind() does not return and likely the probing thread is then blocked and > holds some locks which manifests itself in that the system isn't running stable any > more (e.g. heartbeat LEDs are sometimes stuck although console still works). > > dbg_info() in try_to_bring_up_master() prints: > > [ 102.199362] omapdss_dss 58000000.dss: trying to bring up master > > So I am not sure if this is a panel driver issue at all or the DSI patch set is not > running stable on OMAP5. > > Is a good next step to trace dss_bind() in drivers/gpu/drm/omapdrm//dss/dss.c? There is indeed one kernel worker running at 100% CPU load. top: PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 3196 root 20 0 0 0 0 R 100.0 0.0 2:58.76 kworker/0:8+events More analysis shows that it hangs in drm_client_modeset_probe() in the loop for (i = 0; i < connector_count; i++) total_modes_count += connectors[i]->funcs->fill_modes(connectors[i], width, height); Most likely not in the loop because that looks sane, but connectors[i]->funcs->fill_modes(). So I have to find out what function connectors[i]->funcs->fill_modes is... BTW: connector_count = 2. BR and thanks, Nikolaus
