Re: [REGRESSION] i915: No HDMI output with 4.4

[Daniel Vetter <daniel@ffwll.ch>]

On Mon, Feb 29, 2016 at 03:16:08PM +0000, Sharma, Shashank wrote:
> Please see the latest mail chain, Sonika has already started on it.

Ah ok, crawling through 1k mails after one week of vacation, so I'm still
catching up ;-) My apologies for the confusion.

Thanks, Daniel
> 
> Regards
> Shashank
> 
> -----Original Message-----
> From: Daniel Vetter [mailto:daniel.vetter@ffwll.ch] On Behalf Of Daniel Vetter
> Sent: Monday, February 29, 2016 8:44 PM
> To: Sharma, Shashank
> Cc: Ville Syrjälä; Oleksandr Natalenko; Vetter, Daniel; intel-gfx@lists.freedesktop.org; dri-devel@lists.freedesktop.org; linux-kernel@vger.kernel.org; Daniel Vetter; Jindal, Sonika; Wang, Gary C
> Subject: Re: [REGRESSION] i915: No HDMI output with 4.4
> 
> On Wed, Feb 24, 2016 at 06:07:25AM +0000, Sharma, Shashank wrote:
> > Hi Ville,
> > We will look into this in sometime. Right now team is slightly loaded due to project milestone. 
> > Last time I looked into this, we dint have this HW to reproduce this issue.
> 
> This is an upstream regression. Either you can handle it, or your code must be reverted again. Please either assign someone for this, or send in the patch to revert.
> 
> I'll discuss this with Indranil, too.
> 
> Thanks, Daniel
> > 
> > Regards
> > Shashank
> > -----Original Message-----
> > From: Ville Syrjälä [mailto:ville.syrjala@linux.intel.com]
> > Sent: Tuesday, February 23, 2016 8:38 PM
> > To: Oleksandr Natalenko
> > Cc: Vetter, Daniel; intel-gfx@lists.freedesktop.org; 
> > dri-devel@lists.freedesktop.org; linux-kernel@vger.kernel.org; Daniel 
> > Vetter; Jindal, Sonika; Sharma, Shashank; Wang, Gary C
> > Subject: Re: [REGRESSION] i915: No HDMI output with 4.4
> > 
> > On Mon, Feb 22, 2016 at 02:32:32PM +0200, Oleksandr Natalenko wrote:
> > > Ville, Daniel,
> > > 
> > > any additional info I could provide? I have to return dual-link DVI 
> > > cable back, so let me know if I could reveal more details if necessary.
> > 
> > Unfortunately I'm out of ideas for now. Daniel is on vacation.
> > Anyone else? VPG folks should take the ball here since they broke it.
> > 
> > In the meantime I think as a workaround I think you could use something like video=HDMI-A-1:e on the kernel command line (not sure I got the connector name right for your system). I think that should result in the live status check to be skipped, at least when populating the mode list.
> > 
> > Might be a good idea to collect all the information here and put in a bug report (https://bugs.freedesktop.org/ -> DRI -> DRM/Intel) so that all the logs and such would be in one place.
> > 
> > > 
> > > Regards,
> > >    Oleksandr
> > > 
> > > 16.02.2016 14:54, Daniel Vetter написав:
> > > > On Tue, Feb 16, 2016 at 12:58:56PM +0200, Oleksandr Natalenko wrote:
> > > >> Ville, Daniel,
> > > >> 
> > > >> I've just got another monitor and another DVI-HDMI cable, and 
> > > >> here what I've got.
> > > >> 
> > > >> ===Single Link DVI-D cable with 3 different monitors===
> > > >> 
> > > >> Computer DVI ——— DVI-D (Single Link)/HDMI cable ——— HDMI LG 
> > > >> 23MP65HQ-P === not working
> > > > 
> > > > I presume the above LG screen is what you've called previously 
> > > > "old monitor"?
> > > > 
> > > >> Computer DVI ——— DVI-D (Single Link)/HDMI cable ——— HDMI LG 
> > > >> 23MP67HQ-P === not working Computer DVI ——— DVI-D (Single 
> > > >> Link)/HDMI cable ——— HDMI LG 23MP55HQ-P === works!
> > > >> 
> > > >> ===Dual Link DVI-D cable with monitor that doesn't work with 
> > > >> Single Link cable===
> > > >> 
> > > >> Computer DVI ——— DVI-D (Dual Link)/HDMI cable ——— HDMI LG 
> > > >> 23MP65HQ-P === works!
> > > > 
> > > > Funky. Can you pls grab the debug logs (with the special patches 
> > > > from
> > > > Ville) for this case? I wonder why suddenly different cable and it 
> > > > works.
> > > > 
> > > > Also: Is this one of these older-ish screens where you must have a 
> > > > dual-link cable to drive it at full resolution&refresh rate?
> > > > -Daniel
> > > > 
> > > > 
> > > >> ===Laptop with HDMI output===
> > > >> 
> > > >> Laptop HDMI ——— HDMI/HDMI cable ——— HDMI LG 23MP65HQ-P === works!
> > > >> 
> > > >> I'd say that single link DVI cables are broken with new kernel, 
> > > >> but one of monitors could work with such a cable. So I have no idea :(.
> > > >> 
> > > >> Regards,
> > > >>   Oleksandr.
> > > >> 
> > > >> 15.02.2016 17:42, Daniel Vetter wrote:
> > > >> >The other downside is that it'll make us non-compliant, which 
> > > >> >was the point of this entire ordeal: HDMI spec forbids us from 
> > > >> >starting any i2c transactions when the hpd isn't signalling a present screen.
> > > >> >
> > > >> >So maybe we need to buy one of these broken screens.
> > > >> >
> > > >> >Oleksandr, what exact model are you using? And any chance that 
> > > >> >you could test this on some other machine with intel gfx and 
> > > >> >latest kernel, just to make sure this really is some issue with 
> > > >> >the sink and not with the machine itself? And I guess you've 
> > > >> >tested with some other hdmi sink, and that works?
> > 
> > --
> > Ville Syrjälä
> > Intel OTC
> 
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch