On Wed, Dec 18, 2013 at 10:28:37AM -0600, Daniel Drake wrote: > On Wed, Dec 18, 2013 at 2:43 AM, Daniel Vetter <daniel@xxxxxxxx> wrote: > > I think we can do it simpler. When you get a hpd interrupt you eventually > > call drm_helper_hpd_irq_event which will update all the state and poke > > connectors. I'd just create a delay_work which you launch from > > hdmi_irq_thread with a 1 second delay which again calls > > drm_helper_hpd_irq_event. That way you won't miss the EDID (presuming the > > user isn't _really_ careful with pluggin in the cable slowly). > > OK, I like this more simplistic option. > > However, one more pesky detail, if I am understanding your suggestion > correctly. You are hoping for: > > 1. I connect the display, causing HPD interrupt > 2. hpd irq handler calls drm_helper_hpd_irq_event() directly. Fails to > read EDID, no big deal. > 3. hpd irq handles schedules a work item to call > drm_helper_hpd_irq_event() a second time, 1 second later. Reads EDID > sucessfully, image gets output to display. > > That doesn't quite work. drm_helper_hpd_irq_event() in step 2 notices > and records the state change (disconnected --> connected). And after > drm_helper_probe_single_connector_modes() fails to read the EDID, it > starts outputting an image at 1024x768. When we come to step 3, we > call drm_helper_hpd_irq_event again, but that just returns without > doing anything as it does not detect any new state change. > > If we skip step 2, i.e. always delay the call to > drm_helper_hpd_irq_event by 1 second, the problem is solved. As a > user, the 1 second delay is not noticable. What do you think about > just doing this? Oh right, if you use the hpd pin for detection then this will happen. So I guess always delaying is the right option. Or you could make the connector state only conditional on an edid being present for HDMI, which would also work. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch -- 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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