Hi Daniel, Do you know the issue I mentioned below? Is it a known issue in gfx side? On Haswell ULT, when playing audio on the third pin, DP monitor would cause flicker while HDMI monitor is fine. Thanks --xingchao > -----Original Message----- > From: David Henningsson [mailto:david.henningsson at canonical.com] > Sent: Monday, June 17, 2013 8:15 PM > To: Wang, Xingchao > Cc: Wang Xingchao; tiwai at suse.de; daniel.vetter at ffwll.ch; > alsa-devel at alsa-project.org; intel-gfx at lists.freedesktop.org > Subject: Re: [PATCH 2/4] ALSA: hda - Return error when open empty hdmi > device > > On 06/17/2013 01:54 PM, Wang, Xingchao wrote: > > > >> -----Original Message----- > >> From: David Henningsson [mailto:david.henningsson at canonical.com] > >> Sent: Monday, June 17, 2013 4:24 PM > >> To: Wang Xingchao > >> Cc: tiwai at suse.de; daniel.vetter at ffwll.ch; > >> alsa-devel at alsa-project.org; intel-gfx at lists.freedesktop.org; Wang, > >> Xingchao > >> Subject: Re: [PATCH 2/4] ALSA: hda - Return error when open empty > >> hdmi device > >> > >> On 06/14/2013 05:20 PM, Wang Xingchao wrote: > >>> when user open HDMI device 3/7/8, if it has no physical device > >>> connected, return error. > >> > >> This patch will cause regressions in two big use cases: > >> > >> 1) Older chipsets (at least from non-Intel vendors) might not > >> support correct ELD reporting. Thus this will cause HDMI audio to stop > working there. > > > > Thanks for pointing this out. It's a good case I missed. :) I thought > > ELD info was monitor specific, and reported on common platforms. > > We have a generation of Nvidia cards that does not support presence detect > (and no ELD) for the audio codec at all. > > I'm not sure if we also have cards where presence detect works, but there > never comes any ELD. Or if this can potentially vary depending on the > connected monitor. But I think this should also be handled in the best way. > > > But sometimes user get confused when opening a hdmi device and started > > to play audio,but hear nothing, even there's no error message. Is > > there any way for old chipset which has no correct ELD reporting but do have > audio functionality? App should check before really play audio on the device. > > PulseAudio (with support from some of the GUIs) support looking at the > Presence Detect, and "hiding" the device if nothing is currently connected. > > I agree in principle with that you should be given some warning if you try to play > back to unconnected things, but for me it's not a high priority to improve. > E g, the situation is the same for analog audio - imagine a small desktop with > only a headphone output: you can still play audio to the headphone output even > when there's no headphone connected in the jack. > > >> 2) In PulseAudio's current design, PulseAudio probes the device at > >> startup and caches the result. Unfortunately, there is no reprobing > >> at plug/unplug, so if the monitor is hotplugged, it will not work > >> unless PulseAudio is restarted afterwards. > > > > For haswell ult board only, DDI port D is not supported, this results in > screen flicker when playing on third pin. > > But for other haswell boards, the DDI port D is normal. So at first > > glance my idea is to disable opening device without physical device > connecting. > > Maybe it's possible to fix on the gfx side? It sounds like a graphic driver bug if > the screen flickers due to anything happening on the audio side. > > > > > Thanks > > --xingchao > > > >> > >> > >>> The bug is from Haswell platform, All pins choose converter 0 by > >>> default in hardware level, maybe only pin 1 had valid monitor > >>> connected. if user play audio on pin 0/2, pin 1 can get audio data too. > >>> > >>> Signed-off-by: Wang Xingchao <xingchao.wang at linux.intel.com> > >>> --- > >>> sound/pci/hda/patch_hdmi.c | 3 +++ > >>> 1 file changed, 3 insertions(+) > >>> > >>> diff --git a/sound/pci/hda/patch_hdmi.c b/sound/pci/hda/patch_hdmi.c > >>> index 8db5eb6..d766f40 100644 > >>> --- a/sound/pci/hda/patch_hdmi.c > >>> +++ b/sound/pci/hda/patch_hdmi.c > >>> @@ -1139,6 +1139,9 @@ static int hdmi_pcm_open(struct > >> hda_pcm_stream *hinfo, > >>> per_pin = get_pin(spec, pin_idx); > >>> eld = &per_pin->sink_eld; > >>> > >>> + if (!eld->monitor_present || !eld->eld_valid) > >>> + return -EIO; > >>> + > >>> if (codec->vendor_id == 0x80862807) > >>> hsw_verify_cvt_D0(spec, codec); > >>> > >>> > >> > >> > >> > >> -- > >> David Henningsson, Canonical Ltd. > >> https://launchpad.net/~diwic > > > > > > -- > David Henningsson, Canonical Ltd. > https://launchpad.net/~diwic
