On Mon, Dec 16, 2013 at 5:40 PM, Daniel Vetter <daniel@xxxxxxxx> wrote: > Have a bit of logic in the exynos ->detect function to re-try a 2nd > round of edid probing after each hdp interrupt if the first one > returns an -ENXIO. Only tricky part is to be careful with edge > detection so that userspace gets all the hotplug events still. > Presuming you don't have any funkiness with reprobing causing yet > another hpd interrupt and stuff like that (seen it all), as long as > you're using the helpers in drm_crtc_helper.c it should all be working > correctly. So you want a work item which just grabs all modeset locks > and then calls drm_helper_probe_single_connector_modes or something on > the right connector. Thanks for the tips. Having trouble sticking to those details though. exynos_drm_connector_detect() is actually a long way away from EDID probing so it is hard to detect the ENXIO case there. What happens here is: exynos hdmi_irq_thread() calls drm_helper_hpd_irq_event() That then calls exynos_drm_connector_detect(), which returns a simple "yes, hpd detection says we are connected" Then it calls drm_kms_helper_hotplug_event() for which the call chain is: drm_kms_helper_hotplug_event exynos_drm_output_poll_changed drm_fb_helper_hotplug_event drm_fb_helper_probe_connector_mode exynos_drm_connector_fill_modes drm_helper_probe_single_connector_modes exynos_drm_connector_get_modes drm_get_edid drm_do_get_edid drm_do_probe_ddc_edid <-- ENXIO in here drm_do_probe_ddc_edid actually swallows the ENXIO code and just returns -1, so that particular error is indistinguishable from others. Trying to follow your suggestions, the closest would seem to be something like: 1. Modify exynos_drm_connector_detect to read and cache the EDID right away. If EDID read fails for any reason, report "no connection" and schedule a work item to retry the EDID read. If the later EDID read succeeds, call drm_kms_helper_hotplug_event() 2. Modify exynos_drm_connector_get_modes to return cached EDID Does that sound sensible? Thanks Daniel -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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