Re: -EPROBE_DEFER and failed DSI panel probe
+Thierry and Archit for the drm_panel/panel_bridge bits. Hi all, I'm resurrecting this thread because Eric asked me to find a solution to this problem :-). On Mon, 20 Nov 2017 08:53:05 +0100 Andrzej Hajdawrote: > On 18.11.2017 02:16, Eric Anholt wrote: > > Andrzej Hajda writes: > > > >> On 16.11.2017 21:27, Eric Anholt wrote: > >>> Andrzej Hajda writes: > >>> > On 15.11.2017 21:26, Eric Anholt wrote: > > I'm happy to have the DSI panel finally working on VC4 (just waiting on > > https://lists.freedesktop.org/archives/dri-devel/2017-October/156407.html), > > but now I've got another problem to solve. It would be great if I could > > include the DSI panel in our upstream DT, so that it automatically > > worked when you plugged one in. However, right now we return > > -EPROBE_DEFER during bind unless the panel has actually shown up. This > > means that if you don't have the panel actually connected, you get this > > sequence at startup: > > > > [ 10.719929] [drm] Initialized > > [ 10.829510] vc4_hdmi 3f902000.hdmi: vc4-hdmi-hifi <-> 3f902000.hdmi > > mapping ok > > [ 10.844043] vc4-drm soc:gpu: bound 3f902000.hdmi (ops vc4_hdmi_ops > > [vc4]) > > [ 10.848626] vc4-drm soc:gpu: bound 3f806000.vec (ops vc4_vec_ops > > [vc4]) > > [ 10.850214] vc4-drm soc:gpu: failed to bind 3f70.dsi (ops > > vc4_dsi_ops [vc4]): -517 > > [ 10.856559] vc4-drm soc:gpu: master bind failed: -517 > > > > [...] > > > > [ 10.967718] rpi_touchscreen 3-0045: Atmel I2C read failed: -6 > > > > Once the panel driver fails to probe, we never get asked to re-bind vc4, > > and drm_of_find_panel_or_bridge looks like it would just give us > > -EPROBE_DEFER again since the panel still wasn't registered. Well, that's not surprising since I2C is not an hotplug-friendly bus. So, if you declare a device in the DT, and this device is not accessible (returns I2C errors), that means there's no device at all, and there's no reason for the I2C core to retry later. > > > > Does anyone have any suggestions for handling this? > I guess you should call component_add only when all required resources > are present(including panel), I suppose moving it to vc4_dsi_host_attach > should help. > >>> How can I decide when the panel driver has tried to probe and failed, > >>> versus not tried to probe yet? find_panel_or_bridge gives me > >>> -EPROBE_DEFER either way. We could have a fake/dummy panel object that is registered to the panel list when we know the device will never be available (because it's simply not connected to the control bus). This way, instead of -EPROBE_DEFER, the drm_panel layer could return -ENODEV. But still, this alone won't solve your problem, because, AFAICT, the way the VC4 dev registration work is: "bind all components of the display pipeline, and if there's one missing, do not register the DRM device". So, you'd have to change that for: "only wait for mandatory elements", and then declare the DSI panel as optional (don't know how to encode that in the DT). > >>> > On the other side I am curious why EPROBE_DEFER from bind does not fail > probing of some component (the last one probed), with proper error > propagation it should cause defer_probing of one of the components or > master, and probe/bind should be retried after panel's probe. > >>> The panel probe failed, though, so there's no trigger to re-probe other > >>> drivers. > >> OK, I misunderstood your problem. And after 2nd read I am not sure what > >> do you want to achieve exactly? > >> > >> Do you want to 'hotplug' DSI panel? Or just make it working with and > >> without the panel. In 2nd case other paths (HDMI) should still work, I > >> guess. > > Yeah, the second thing. I would like to use a single DT to describe a > > platform where the panel may or may not be present, so the panel driver > > (panel-raspberrypi-touchscreen.c) will throw an error from the I2C part > > of the probe or not instead of creating the DSI device and attaching the > > panel. > > > >> Lets assume that you are interested in the latter case. There could be > >> multiple solutions more or less hacky: > >> > >> 1. Use connector's HPD infrastructure to signal presence of the panel, > >> ie. in mipi_dsi::host_(attach|detach) callback you grab the panel and > >> change connector status to connected|disconnected and calls > >> drm_kms_helper_hotplug_event, it is done this way in > >> exynos_dsi_host_attach. > > This is basically what I had before all the review reworks, and the > > regression from this state is keeping me from merging the current driver > > downstream. > > > > This option is unfortunate because we'll have forced *some* output on at > > boot time, and then when the panel driver shows up later we don't resize > > the
Re: -EPROBE_DEFER and failed DSI panel probe
Daniel Vetterwrites: > On Mon, Nov 20, 2017 at 08:53:05AM +0100, Andrzej Hajda wrote: >> On 18.11.2017 02:16, Eric Anholt wrote: >> > Andrzej Hajda writes: >> > >> >> On 16.11.2017 21:27, Eric Anholt wrote: >> >>> Andrzej Hajda writes: >> >>> >> On 15.11.2017 21:26, Eric Anholt wrote: >> > I'm happy to have the DSI panel finally working on VC4 (just waiting on >> > https://lists.freedesktop.org/archives/dri-devel/2017-October/156407.html), >> > but now I've got another problem to solve. It would be great if I >> > could >> > include the DSI panel in our upstream DT, so that it automatically >> > worked when you plugged one in. However, right now we return >> > -EPROBE_DEFER during bind unless the panel has actually shown up. This >> > means that if you don't have the panel actually connected, you get this >> > sequence at startup: >> > >> > [ 10.719929] [drm] Initialized >> > [ 10.829510] vc4_hdmi 3f902000.hdmi: vc4-hdmi-hifi <-> 3f902000.hdmi >> > mapping ok >> > [ 10.844043] vc4-drm soc:gpu: bound 3f902000.hdmi (ops vc4_hdmi_ops >> > [vc4]) >> > [ 10.848626] vc4-drm soc:gpu: bound 3f806000.vec (ops vc4_vec_ops >> > [vc4]) >> > [ 10.850214] vc4-drm soc:gpu: failed to bind 3f70.dsi (ops >> > vc4_dsi_ops [vc4]): -517 >> > [ 10.856559] vc4-drm soc:gpu: master bind failed: -517 >> > >> > [...] >> > >> > [ 10.967718] rpi_touchscreen 3-0045: Atmel I2C read failed: -6 >> > >> > Once the panel driver fails to probe, we never get asked to re-bind >> > vc4, >> > and drm_of_find_panel_or_bridge looks like it would just give us >> > -EPROBE_DEFER again since the panel still wasn't registered. >> > >> > Does anyone have any suggestions for handling this? >> I guess you should call component_add only when all required resources >> are present(including panel), I suppose moving it to vc4_dsi_host_attach >> should help. >> >>> How can I decide when the panel driver has tried to probe and failed, >> >>> versus not tried to probe yet? find_panel_or_bridge gives me >> >>> -EPROBE_DEFER either way. >> >>> >> On the other side I am curious why EPROBE_DEFER from bind does not fail >> probing of some component (the last one probed), with proper error >> propagation it should cause defer_probing of one of the components or >> master, and probe/bind should be retried after panel's probe. >> >>> The panel probe failed, though, so there's no trigger to re-probe other >> >>> drivers. >> >> OK, I misunderstood your problem. And after 2nd read I am not sure what >> >> do you want to achieve exactly? >> >> >> >> Do you want to 'hotplug' DSI panel? Or just make it working with and >> >> without the panel. In 2nd case other paths (HDMI) should still work, I >> >> guess. >> > Yeah, the second thing. I would like to use a single DT to describe a >> > platform where the panel may or may not be present, so the panel driver >> > (panel-raspberrypi-touchscreen.c) will throw an error from the I2C part >> > of the probe or not instead of creating the DSI device and attaching the >> > panel. >> > >> >> Lets assume that you are interested in the latter case. There could be >> >> multiple solutions more or less hacky: >> >> >> >> 1. Use connector's HPD infrastructure to signal presence of the panel, >> >> ie. in mipi_dsi::host_(attach|detach) callback you grab the panel and >> >> change connector status to connected|disconnected and calls >> >> drm_kms_helper_hotplug_event, it is done this way in >> >> exynos_dsi_host_attach. >> > This is basically what I had before all the review reworks, and the >> > regression from this state is keeping me from merging the current driver >> > downstream. >> > >> > This option is unfortunate because we'll have forced *some* output on at >> > boot time, and then when the panel driver shows up later we don't resize >> > the fbcon to the panel's size. >> >> This issue can be solved using deffered fbdev registration, ie fbdev is >> registered after some connector(or specific one, up to you) becomes >> connected. > > Just jumping on on this part here: Deferred fbdev probe is merged now, > which means as long as really nothing is connected, fbdev won't force > anything. > > The exception is still analog outputs where we report "unknown", in that > case fbdev still tries to light that up right away, just in case. Not sure > that applies to the rpi with the tv-out. Yeah, TV-out reports unknown for us as well. signature.asc Description: PGP signature ___ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
Re: -EPROBE_DEFER and failed DSI panel probe
On Wed, Nov 15, 2017 at 2:26 PM, Eric Anholtwrote: > I'm happy to have the DSI panel finally working on VC4 (just waiting on > https://lists.freedesktop.org/archives/dri-devel/2017-October/156407.html), > but now I've got another problem to solve. It would be great if I could > include the DSI panel in our upstream DT, so that it automatically > worked when you plugged one in. However, right now we return > -EPROBE_DEFER during bind unless the panel has actually shown up. This > means that if you don't have the panel actually connected, you get this > sequence at startup: > > [ 10.719929] [drm] Initialized > [ 10.829510] vc4_hdmi 3f902000.hdmi: vc4-hdmi-hifi <-> 3f902000.hdmi > mapping ok > [ 10.844043] vc4-drm soc:gpu: bound 3f902000.hdmi (ops vc4_hdmi_ops [vc4]) > [ 10.848626] vc4-drm soc:gpu: bound 3f806000.vec (ops vc4_vec_ops [vc4]) > [ 10.850214] vc4-drm soc:gpu: failed to bind 3f70.dsi (ops vc4_dsi_ops > [vc4]): -517 > [ 10.856559] vc4-drm soc:gpu: master bind failed: -517 > > [...] > > [ 10.967718] rpi_touchscreen 3-0045: Atmel I2C read failed: -6 > > Once the panel driver fails to probe, we never get asked to re-bind vc4, > and drm_of_find_panel_or_bridge looks like it would just give us > -EPROBE_DEFER again since the panel still wasn't registered. > > Does anyone have any suggestions for handling this? You can modify the live DT marking the panel disabled (updating/adding the status property) in the rpi_touchscreen probe. Then you would need to get the status property re-read on the panel node which I'm not sure would happen currently. Getting this latter part working would be useful also for cases were applying a DT overlay enables/disables a panel. Rob ___ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
Re: -EPROBE_DEFER and failed DSI panel probe
On Mon, Nov 20, 2017 at 08:53:05AM +0100, Andrzej Hajda wrote: > On 18.11.2017 02:16, Eric Anholt wrote: > > Andrzej Hajdawrites: > > > >> On 16.11.2017 21:27, Eric Anholt wrote: > >>> Andrzej Hajda writes: > >>> > On 15.11.2017 21:26, Eric Anholt wrote: > > I'm happy to have the DSI panel finally working on VC4 (just waiting on > > https://lists.freedesktop.org/archives/dri-devel/2017-October/156407.html), > > but now I've got another problem to solve. It would be great if I could > > include the DSI panel in our upstream DT, so that it automatically > > worked when you plugged one in. However, right now we return > > -EPROBE_DEFER during bind unless the panel has actually shown up. This > > means that if you don't have the panel actually connected, you get this > > sequence at startup: > > > > [ 10.719929] [drm] Initialized > > [ 10.829510] vc4_hdmi 3f902000.hdmi: vc4-hdmi-hifi <-> 3f902000.hdmi > > mapping ok > > [ 10.844043] vc4-drm soc:gpu: bound 3f902000.hdmi (ops vc4_hdmi_ops > > [vc4]) > > [ 10.848626] vc4-drm soc:gpu: bound 3f806000.vec (ops vc4_vec_ops > > [vc4]) > > [ 10.850214] vc4-drm soc:gpu: failed to bind 3f70.dsi (ops > > vc4_dsi_ops [vc4]): -517 > > [ 10.856559] vc4-drm soc:gpu: master bind failed: -517 > > > > [...] > > > > [ 10.967718] rpi_touchscreen 3-0045: Atmel I2C read failed: -6 > > > > Once the panel driver fails to probe, we never get asked to re-bind vc4, > > and drm_of_find_panel_or_bridge looks like it would just give us > > -EPROBE_DEFER again since the panel still wasn't registered. > > > > Does anyone have any suggestions for handling this? > I guess you should call component_add only when all required resources > are present(including panel), I suppose moving it to vc4_dsi_host_attach > should help. > >>> How can I decide when the panel driver has tried to probe and failed, > >>> versus not tried to probe yet? find_panel_or_bridge gives me > >>> -EPROBE_DEFER either way. > >>> > On the other side I am curious why EPROBE_DEFER from bind does not fail > probing of some component (the last one probed), with proper error > propagation it should cause defer_probing of one of the components or > master, and probe/bind should be retried after panel's probe. > >>> The panel probe failed, though, so there's no trigger to re-probe other > >>> drivers. > >> OK, I misunderstood your problem. And after 2nd read I am not sure what > >> do you want to achieve exactly? > >> > >> Do you want to 'hotplug' DSI panel? Or just make it working with and > >> without the panel. In 2nd case other paths (HDMI) should still work, I > >> guess. > > Yeah, the second thing. I would like to use a single DT to describe a > > platform where the panel may or may not be present, so the panel driver > > (panel-raspberrypi-touchscreen.c) will throw an error from the I2C part > > of the probe or not instead of creating the DSI device and attaching the > > panel. > > > >> Lets assume that you are interested in the latter case. There could be > >> multiple solutions more or less hacky: > >> > >> 1. Use connector's HPD infrastructure to signal presence of the panel, > >> ie. in mipi_dsi::host_(attach|detach) callback you grab the panel and > >> change connector status to connected|disconnected and calls > >> drm_kms_helper_hotplug_event, it is done this way in > >> exynos_dsi_host_attach. > > This is basically what I had before all the review reworks, and the > > regression from this state is keeping me from merging the current driver > > downstream. > > > > This option is unfortunate because we'll have forced *some* output on at > > boot time, and then when the panel driver shows up later we don't resize > > the fbcon to the panel's size. > > This issue can be solved using deffered fbdev registration, ie fbdev is > registered after some connector(or specific one, up to you) becomes > connected. Just jumping on on this part here: Deferred fbdev probe is merged now, which means as long as really nothing is connected, fbdev won't force anything. The exception is still analog outputs where we report "unknown", in that case fbdev still tries to light that up right away, just in case. Not sure that applies to the rpi with the tv-out. I guess it'd be lovely if we could re-plug the fbdev emulation when a new connector shows up (at least if it's of type panel maybe), so to avoid the dreaded "my fbcon is totally wrong" problem. I think with all the fbdev rework and drm connector hotplug support this should be doable. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch ___ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
Re: -EPROBE_DEFER and failed DSI panel probe
On 18.11.2017 02:16, Eric Anholt wrote: > Andrzej Hajdawrites: > >> On 16.11.2017 21:27, Eric Anholt wrote: >>> Andrzej Hajda writes: >>> On 15.11.2017 21:26, Eric Anholt wrote: > I'm happy to have the DSI panel finally working on VC4 (just waiting on > https://lists.freedesktop.org/archives/dri-devel/2017-October/156407.html), > but now I've got another problem to solve. It would be great if I could > include the DSI panel in our upstream DT, so that it automatically > worked when you plugged one in. However, right now we return > -EPROBE_DEFER during bind unless the panel has actually shown up. This > means that if you don't have the panel actually connected, you get this > sequence at startup: > > [ 10.719929] [drm] Initialized > [ 10.829510] vc4_hdmi 3f902000.hdmi: vc4-hdmi-hifi <-> 3f902000.hdmi > mapping ok > [ 10.844043] vc4-drm soc:gpu: bound 3f902000.hdmi (ops vc4_hdmi_ops > [vc4]) > [ 10.848626] vc4-drm soc:gpu: bound 3f806000.vec (ops vc4_vec_ops [vc4]) > [ 10.850214] vc4-drm soc:gpu: failed to bind 3f70.dsi (ops > vc4_dsi_ops [vc4]): -517 > [ 10.856559] vc4-drm soc:gpu: master bind failed: -517 > > [...] > > [ 10.967718] rpi_touchscreen 3-0045: Atmel I2C read failed: -6 > > Once the panel driver fails to probe, we never get asked to re-bind vc4, > and drm_of_find_panel_or_bridge looks like it would just give us > -EPROBE_DEFER again since the panel still wasn't registered. > > Does anyone have any suggestions for handling this? I guess you should call component_add only when all required resources are present(including panel), I suppose moving it to vc4_dsi_host_attach should help. >>> How can I decide when the panel driver has tried to probe and failed, >>> versus not tried to probe yet? find_panel_or_bridge gives me >>> -EPROBE_DEFER either way. >>> On the other side I am curious why EPROBE_DEFER from bind does not fail probing of some component (the last one probed), with proper error propagation it should cause defer_probing of one of the components or master, and probe/bind should be retried after panel's probe. >>> The panel probe failed, though, so there's no trigger to re-probe other >>> drivers. >> OK, I misunderstood your problem. And after 2nd read I am not sure what >> do you want to achieve exactly? >> >> Do you want to 'hotplug' DSI panel? Or just make it working with and >> without the panel. In 2nd case other paths (HDMI) should still work, I >> guess. > Yeah, the second thing. I would like to use a single DT to describe a > platform where the panel may or may not be present, so the panel driver > (panel-raspberrypi-touchscreen.c) will throw an error from the I2C part > of the probe or not instead of creating the DSI device and attaching the > panel. > >> Lets assume that you are interested in the latter case. There could be >> multiple solutions more or less hacky: >> >> 1. Use connector's HPD infrastructure to signal presence of the panel, >> ie. in mipi_dsi::host_(attach|detach) callback you grab the panel and >> change connector status to connected|disconnected and calls >> drm_kms_helper_hotplug_event, it is done this way in exynos_dsi_host_attach. > This is basically what I had before all the review reworks, and the > regression from this state is keeping me from merging the current driver > downstream. > > This option is unfortunate because we'll have forced *some* output on at > boot time, and then when the panel driver shows up later we don't resize > the fbcon to the panel's size. This issue can be solved using deffered fbdev registration, ie fbdev is registered after some connector(or specific one, up to you) becomes connected. > >> 2. Check for presence of the panel's driver before registering the bus, >> if not present defer probing (but I am not sure if driver's registration >> will trigger deferred probing, should be checked). >> >> This way if the panel's driver is present during mipi bus registration >> and after that panel should be bound to the drivers, otherwise it means >> probe failed. This solutions requires discovering panels compatible in >> DSI driver. Quite complicated and very hacky. > Restating to see if I understand: Defer all of VC4, including its MIPI > host registration, until we see the panel driver loaded (how would one > do that?). > Then once we get reprobed with the MIPI driver present > (would that even happen?), register our MIPI bus and continue on to > component bind. In component bind, don't defer if we don't find the > panel, because we know the panel driver had a chance to probe and attach > right away when our bus showed up. Yes this is the rough idea. I have assumed you have panel on DSI bus, but from your response it seems you have panel controlled via i2c bus and having DSI data bus. I am not sure if
Re: -EPROBE_DEFER and failed DSI panel probe
Andrzej Hajdawrites: > On 16.11.2017 21:27, Eric Anholt wrote: >> Andrzej Hajda writes: >> >>> On 15.11.2017 21:26, Eric Anholt wrote: I'm happy to have the DSI panel finally working on VC4 (just waiting on https://lists.freedesktop.org/archives/dri-devel/2017-October/156407.html), but now I've got another problem to solve. It would be great if I could include the DSI panel in our upstream DT, so that it automatically worked when you plugged one in. However, right now we return -EPROBE_DEFER during bind unless the panel has actually shown up. This means that if you don't have the panel actually connected, you get this sequence at startup: [ 10.719929] [drm] Initialized [ 10.829510] vc4_hdmi 3f902000.hdmi: vc4-hdmi-hifi <-> 3f902000.hdmi mapping ok [ 10.844043] vc4-drm soc:gpu: bound 3f902000.hdmi (ops vc4_hdmi_ops [vc4]) [ 10.848626] vc4-drm soc:gpu: bound 3f806000.vec (ops vc4_vec_ops [vc4]) [ 10.850214] vc4-drm soc:gpu: failed to bind 3f70.dsi (ops vc4_dsi_ops [vc4]): -517 [ 10.856559] vc4-drm soc:gpu: master bind failed: -517 [...] [ 10.967718] rpi_touchscreen 3-0045: Atmel I2C read failed: -6 Once the panel driver fails to probe, we never get asked to re-bind vc4, and drm_of_find_panel_or_bridge looks like it would just give us -EPROBE_DEFER again since the panel still wasn't registered. Does anyone have any suggestions for handling this? >>> I guess you should call component_add only when all required resources >>> are present(including panel), I suppose moving it to vc4_dsi_host_attach >>> should help. >> How can I decide when the panel driver has tried to probe and failed, >> versus not tried to probe yet? find_panel_or_bridge gives me >> -EPROBE_DEFER either way. >> >>> On the other side I am curious why EPROBE_DEFER from bind does not fail >>> probing of some component (the last one probed), with proper error >>> propagation it should cause defer_probing of one of the components or >>> master, and probe/bind should be retried after panel's probe. >> The panel probe failed, though, so there's no trigger to re-probe other >> drivers. > > OK, I misunderstood your problem. And after 2nd read I am not sure what > do you want to achieve exactly? > > Do you want to 'hotplug' DSI panel? Or just make it working with and > without the panel. In 2nd case other paths (HDMI) should still work, I > guess. Yeah, the second thing. I would like to use a single DT to describe a platform where the panel may or may not be present, so the panel driver (panel-raspberrypi-touchscreen.c) will throw an error from the I2C part of the probe or not instead of creating the DSI device and attaching the panel. > Lets assume that you are interested in the latter case. There could be > multiple solutions more or less hacky: > > 1. Use connector's HPD infrastructure to signal presence of the panel, > ie. in mipi_dsi::host_(attach|detach) callback you grab the panel and > change connector status to connected|disconnected and calls > drm_kms_helper_hotplug_event, it is done this way in exynos_dsi_host_attach. This is basically what I had before all the review reworks, and the regression from this state is keeping me from merging the current driver downstream. This option is unfortunate because we'll have forced *some* output on at boot time, and then when the panel driver shows up later we don't resize the fbcon to the panel's size. > 2. Check for presence of the panel's driver before registering the bus, > if not present defer probing (but I am not sure if driver's registration > will trigger deferred probing, should be checked). > > This way if the panel's driver is present during mipi bus registration > and after that panel should be bound to the drivers, otherwise it means > probe failed. This solutions requires discovering panels compatible in > DSI driver. Quite complicated and very hacky. Restating to see if I understand: Defer all of VC4, including its MIPI host registration, until we see the panel driver loaded (how would one do that?). Then once we get reprobed with the MIPI driver present (would that even happen?), register our MIPI bus and continue on to component bind. In component bind, don't defer if we don't find the panel, because we know the panel driver had a chance to probe and attach right away when our bus showed up. > 3. In panel's probe attach the panel to the bus before hardware probe > and detach it if the physical panel is not present. This way dsi host > callbacks will be called and can be used to discover failed probes. If the I2C driver's probe fails, what ends up freeing the panel or DSI host driver that the I2C driver allocated when the module is unloaded? signature.asc Description: PGP signature ___ dri-devel mailing list
Re: -EPROBE_DEFER and failed DSI panel probe
On 16.11.2017 21:27, Eric Anholt wrote: > Andrzej Hajdawrites: > >> On 15.11.2017 21:26, Eric Anholt wrote: >>> I'm happy to have the DSI panel finally working on VC4 (just waiting on >>> https://lists.freedesktop.org/archives/dri-devel/2017-October/156407.html), >>> but now I've got another problem to solve. It would be great if I could >>> include the DSI panel in our upstream DT, so that it automatically >>> worked when you plugged one in. However, right now we return >>> -EPROBE_DEFER during bind unless the panel has actually shown up. This >>> means that if you don't have the panel actually connected, you get this >>> sequence at startup: >>> >>> [ 10.719929] [drm] Initialized >>> [ 10.829510] vc4_hdmi 3f902000.hdmi: vc4-hdmi-hifi <-> 3f902000.hdmi >>> mapping ok >>> [ 10.844043] vc4-drm soc:gpu: bound 3f902000.hdmi (ops vc4_hdmi_ops [vc4]) >>> [ 10.848626] vc4-drm soc:gpu: bound 3f806000.vec (ops vc4_vec_ops [vc4]) >>> [ 10.850214] vc4-drm soc:gpu: failed to bind 3f70.dsi (ops >>> vc4_dsi_ops [vc4]): -517 >>> [ 10.856559] vc4-drm soc:gpu: master bind failed: -517 >>> >>> [...] >>> >>> [ 10.967718] rpi_touchscreen 3-0045: Atmel I2C read failed: -6 >>> >>> Once the panel driver fails to probe, we never get asked to re-bind vc4, >>> and drm_of_find_panel_or_bridge looks like it would just give us >>> -EPROBE_DEFER again since the panel still wasn't registered. >>> >>> Does anyone have any suggestions for handling this? >> I guess you should call component_add only when all required resources >> are present(including panel), I suppose moving it to vc4_dsi_host_attach >> should help. > How can I decide when the panel driver has tried to probe and failed, > versus not tried to probe yet? find_panel_or_bridge gives me > -EPROBE_DEFER either way. > >> On the other side I am curious why EPROBE_DEFER from bind does not fail >> probing of some component (the last one probed), with proper error >> propagation it should cause defer_probing of one of the components or >> master, and probe/bind should be retried after panel's probe. > The panel probe failed, though, so there's no trigger to re-probe other > drivers. OK, I misunderstood your problem. And after 2nd read I am not sure what do you want to achieve exactly? Do you want to 'hotplug' DSI panel? Or just make it working with and without the panel. In 2nd case other paths (HDMI) should still work, I guess. Lets assume that you are interested in the latter case. There could be multiple solutions more or less hacky: 1. Use connector's HPD infrastructure to signal presence of the panel, ie. in mipi_dsi::host_(attach|detach) callback you grab the panel and change connector status to connected|disconnected and calls drm_kms_helper_hotplug_event, it is done this way in exynos_dsi_host_attach. 2. Check for presence of the panel's driver before registering the bus, if not present defer probing (but I am not sure if driver's registration will trigger deferred probing, should be checked). This way if the panel's driver is present during mipi bus registration and after that panel should be bound to the drivers, otherwise it means probe failed. This solutions requires discovering panels compatible in DSI driver. Quite complicated and very hacky. 3. In panel's probe attach the panel to the bus before hardware probe and detach it if the physical panel is not present. This way dsi host callbacks will be called and can be used to discover failed probes. Regards Andrzej ___ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
Re: -EPROBE_DEFER and failed DSI panel probe
Andrzej Hajdawrites: > On 15.11.2017 21:26, Eric Anholt wrote: >> I'm happy to have the DSI panel finally working on VC4 (just waiting on >> https://lists.freedesktop.org/archives/dri-devel/2017-October/156407.html), >> but now I've got another problem to solve. It would be great if I could >> include the DSI panel in our upstream DT, so that it automatically >> worked when you plugged one in. However, right now we return >> -EPROBE_DEFER during bind unless the panel has actually shown up. This >> means that if you don't have the panel actually connected, you get this >> sequence at startup: >> >> [ 10.719929] [drm] Initialized >> [ 10.829510] vc4_hdmi 3f902000.hdmi: vc4-hdmi-hifi <-> 3f902000.hdmi >> mapping ok >> [ 10.844043] vc4-drm soc:gpu: bound 3f902000.hdmi (ops vc4_hdmi_ops [vc4]) >> [ 10.848626] vc4-drm soc:gpu: bound 3f806000.vec (ops vc4_vec_ops [vc4]) >> [ 10.850214] vc4-drm soc:gpu: failed to bind 3f70.dsi (ops vc4_dsi_ops >> [vc4]): -517 >> [ 10.856559] vc4-drm soc:gpu: master bind failed: -517 >> >> [...] >> >> [ 10.967718] rpi_touchscreen 3-0045: Atmel I2C read failed: -6 >> >> Once the panel driver fails to probe, we never get asked to re-bind vc4, >> and drm_of_find_panel_or_bridge looks like it would just give us >> -EPROBE_DEFER again since the panel still wasn't registered. >> >> Does anyone have any suggestions for handling this? > > I guess you should call component_add only when all required resources > are present(including panel), I suppose moving it to vc4_dsi_host_attach > should help. How can I decide when the panel driver has tried to probe and failed, versus not tried to probe yet? find_panel_or_bridge gives me -EPROBE_DEFER either way. > On the other side I am curious why EPROBE_DEFER from bind does not fail > probing of some component (the last one probed), with proper error > propagation it should cause defer_probing of one of the components or > master, and probe/bind should be retried after panel's probe. The panel probe failed, though, so there's no trigger to re-probe other drivers. signature.asc Description: PGP signature ___ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
Re: -EPROBE_DEFER and failed DSI panel probe
On 15.11.2017 21:26, Eric Anholt wrote: > I'm happy to have the DSI panel finally working on VC4 (just waiting on > https://lists.freedesktop.org/archives/dri-devel/2017-October/156407.html), > but now I've got another problem to solve. It would be great if I could > include the DSI panel in our upstream DT, so that it automatically > worked when you plugged one in. However, right now we return > -EPROBE_DEFER during bind unless the panel has actually shown up. This > means that if you don't have the panel actually connected, you get this > sequence at startup: > > [ 10.719929] [drm] Initialized > [ 10.829510] vc4_hdmi 3f902000.hdmi: vc4-hdmi-hifi <-> 3f902000.hdmi > mapping ok > [ 10.844043] vc4-drm soc:gpu: bound 3f902000.hdmi (ops vc4_hdmi_ops [vc4]) > [ 10.848626] vc4-drm soc:gpu: bound 3f806000.vec (ops vc4_vec_ops [vc4]) > [ 10.850214] vc4-drm soc:gpu: failed to bind 3f70.dsi (ops vc4_dsi_ops > [vc4]): -517 > [ 10.856559] vc4-drm soc:gpu: master bind failed: -517 > > [...] > > [ 10.967718] rpi_touchscreen 3-0045: Atmel I2C read failed: -6 > > Once the panel driver fails to probe, we never get asked to re-bind vc4, > and drm_of_find_panel_or_bridge looks like it would just give us > -EPROBE_DEFER again since the panel still wasn't registered. > > Does anyone have any suggestions for handling this? I guess you should call component_add only when all required resources are present(including panel), I suppose moving it to vc4_dsi_host_attach should help. Another (maybe better) solution is to look for panel after mipi_dsi_host_register, but before component_add, and fail if the panel is not present. On the other side I am curious why EPROBE_DEFER from bind does not fail probing of some component (the last one probed), with proper error propagation it should cause defer_probing of one of the components or master, and probe/bind should be retried after panel's probe. Regards Andrzej > > > ___ > dri-devel mailing list > dri-devel@lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel ___ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel