On Mon, 2012-09-17 at 11:32 +0200, Takashi Iwai wrote: > At Mon, 17 Sep 2012 19:11:34 +1000, > Dave Airlie wrote: > > On Mon, Sep 17, 2012 at 6:28 PM, Takashi Iwai <tiwai at suse.de> wrote: > > > At Mon, 17 Sep 2012 18:21:47 +1000, > > > Dave Airlie wrote: > > >> On Mon, Sep 17, 2012 at 6:16 PM, Takashi Iwai <tiwai at suse.de> wrote: > > >> > At Fri, 14 Sep 2012 11:25:03 -0400, > > >> > Adam Jackson wrote: > > >> >> > > >> >> Can you be more specific here? What DPCD does it return? > > >> > > > >> > It shows "DPCD: 110a820100030181" So dpcd[0x5] is 0x03, and drm_dp_helper.h says: #define DP_DOWNSTREAMPORT_PRESENT 0x005 # define DP_DWN_STRM_PORT_PRESENT (1 << 0) # define DP_DWN_STRM_PORT_TYPE_MASK 0x06 /* 00b = DisplayPort */ /* 01b = Analog */ /* 10b = TMDS or HDMI */ /* 11b = Other */ # define DP_FORMAT_CONVERSION (1 << 3) So there we go, it's a branch device with VGA downstream of it. We need to figure out the connectivity of the downstream port. > > > Checking DPCD bits might work, but I have no exact spec of DPCD, so no > > > idea whether the above is really wrong or not. > > > > Is there a VGA port on the docking station, it might have a DP->VGA in > > it, or dual-link DVI port. > > Ah, right, that's the missing piece! > > It's a DP->VGA conversion indeed. Plugging to a VGA connector appears > as DP2. Oh well, I didn't think of this possibility at all. > > But then this makes me wonder how to solve the problem at best. > It's obviously a bogus connection status returned from the driver. > DP2 advertises itself as if connected. I wouldn't quite say it's bogus, more that we're describing the connection status of "the nearest DP device" as if it were the connection status of the whole wire. I started a patch series for this a bit ago, I'll send it on momentarily. - 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/20120917/f0c74e01/attachment.pgp>
