linux-kernel - Re: [REGRESSION] i915: No HDMI output with 4.4

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Message-ID: <a90b41a8bf714c9ba5a8f4206c94964f@natalenko.name>
Date:	Mon, 15 Feb 2016 09:57:06 +0200
From:	Oleksandr Natalenko <oleksandr@...alenko.name>
To:	Ville Syrjälä <ville.syrjala@...ux.intel.com>
Cc:	Daniel Vetter <daniel.vetter@...el.com>,
	intel-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org,
	Daniel Vetter <daniel.vetter@...ll.ch>
Subject: Re: [REGRESSION] i915: No HDMI output with 4.4

Hi, Ville.

13.02.2016 01:23, Ville Syrjälä wrote:
> Few other ideas:
> - Was the monitor sleeping when you tried this? Can you maybe push
>   some button on it and then immediately run the intel_reg read command
>   again?

Nope. It just goes to sleep mode after (I suppose) drm module is loaded. 
Before module gets loaded monitor displays console as it should and does 
not sleep. However, I've tried to switch monitor inputs as well as 
pushing power button with no luck.

> - Do you have another monitor to try?
> - Do you have another cable to try?

Will find that.

> - Maybe the pullup/down on the hpd line is misconfigured or something.
>   Any chance of updating the BIOS on the machine?

===
Base Board Information
         Manufacturer: ASUSTeK COMPUTER INC.
         Product Name: H61M-K
BIOS Information
         Vendor: American Megatrends Inc.
         Version: 0801
         Release Date: 07/21/2014
===

0801 is the latest available for this board.

> - What does 'intel_reg read 0xc2000 0xc2004 0xc2020' say?

===
                                     (0x000c2000): 0x00000000
                                     (0x000c2004): 0x00000001
                                     (0x000c2020): 0x60004000
===

> - The spec claims the TMDS vs. SDVO select has something to do with
>   hpd generation. I can't see any difference on my IVB though, so not
>   sure it's really true.
> 
>   What does 'intel_reg read 0xe1140 0xe1150 0xe1160' tell us?

===
                               HDMIB (0x000e1140): 0x00000018 (disabled 
pipe A 8bpc SDVO DVI audio disabled +vsync +hsync non-detected)
                               HDMIC (0x000e1150): 0x00000804 (disabled 
pipe A 8bpc TMDS DVI audio disabled -vsync -hsync detected)
                               HDMID (0x000e1160): 0x00000018 (disabled 
pipe A 8bpc SDVO DVI audio disabled +vsync +hsync non-detected)
===

>   Let's try these anyway (with the cable plugged in):
> 
>   intel_reg write 0xe1140 0x0
>   intel_reg write 0xe1150 0x0
>   intel_reg write 0xe1160 0x0
>   sleep 1
>   intel_reg read 0xc4000
> 
>   intel_reg write 0xe1140 0x800
>   intel_reg write 0xe1150 0x800
>   intel_reg write 0xe1160 0x800
>   sleep 1
>   intel_reg read 0xc4000
> 
>   intel_reg write 0xe1140 0x800800
>   intel_reg write 0xe1150 0x800800
>   intel_reg write 0xe1160 0x800800
>   sleep 1
>   intel_reg read 0xc4000
> 
>   intel_reg write 0xe1140 0x800000
>   intel_reg write 0xe1150 0x800000
>   intel_reg write 0xe1160 0x800000
>   sleep 1
>   intel_reg read 0xc4000
> 

Same output for all 4 sets of commands:

===
                                     (0x000c4000): 0x00000000
===

Regards,
   Oleksandr.