On Tue, 2012-09-18 at 13:01 +0200, Takashi Iwai wrote: > > I started a patch series for this a bit ago, I'll send it on > > momentarily. > > Thanks! I evaluated it now (with a typo fix suggested by Jani). > Unfortunately, it doesn't improve the situation. > > The fetch of downstream ports succeeds, and it gets 0x09. So, this > indicates again it's a VGA downstream port. But that's all, so far. > The 0x09 is reported no matter whether the VGA cable is plugged or > not, so this can't be used as the detection of the downstream port > plug state. Sorry, there's a bug in the patch. link_configuration[0] is not DP_SINK_COUNT, I have no idea why I thought it was. Try this on top of the series: === diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index 9809c53..b6b9a18 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -2098,15 +2098,22 @@ intel_dp_detect_dpcd(struct intel_dp *intel_dp) if (!intel_dp_get_dpcd(intel_dp)) return connector_status_disconnected; - + /* if there's no downstream port, we're done */ if (!(dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_PRESENT)) return connector_status_connected; /* If we're HPD-aware, SINK_COUNT changes dynamically */ hpd = !!(intel_dp->downstream_ports[0] & DP_DS_PORT_HPD); - if (hpd && (intel_dp->link_configuration[0] & DP_SINK_COUNT_MASK)) - return connector_status_connected; + if (hpd) { + uint8_t sink_count; + if (!intel_dp_aux_native_read_retry(intel_dp, DP_SINK_COUNT, + &sink_count, 1)) + return connector_status_unknown; + sink_count &= DP_SINK_COUNT_MASK; + return sink_count ? connector_status_connected + : connector_status_disconnected; + } /* If no HPD, poke DDC gently */ if (drm_probe_ddc(&intel_dp->adapter)) === If that doesn't work then the HPD-capable bit is useless - or if we're lucky just needs quirking by branch OUI - and we should just fall through to the drm_probe_ddc() path. What is the branch OUI, anyway? There's a third possibility, which is that HPD does work but that we're not doing enough to enable it. The DP 1.1a spec has a non-normative appendix describing one way a device could go about doing that as an optional feature, but the method described does not match how we're currently handling sink-specific IRQs. I have no idea what the 1.2 spec says on this point though. - ajax -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 198 bytes Desc: This is a digitally signed message part URL: <http://lists.freedesktop.org/archives/intel-gfx/attachments/20120918/8c8cecd5/attachment.pgp>