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From: Jani Nikula <jani.nikula@linux.intel.com>
To: Rob Kramer <rob@solution-space.com>, dri-devel@lists.freedesktop.org
Cc: intel-gfx@lists.freedesktop.org
Subject: Re: Troubleshooting LVDS on GM45.
Date: Fri, 01 Apr 2016 11:01:36 +0300	[thread overview]
Message-ID: <874mbl21wf.fsf@intel.com> (raw)
In-Reply-To: <56FDFDBE.1020809@solution-space.com>

On Fri, 01 Apr 2016, Rob Kramer <rob@solution-space.com> wrote:
> My setup is an embedded GM45 based board with a screen connected via 24 
> bit LVDS. When trying a to use a newer kernel (3.14.57) with KMS, the 
> screen stays blank. I'm only testing KMS so far, no X. Older, pre-KMS 
> versions of the kernel worked fine.
>
> I'm hoping that a resident Intel DRM guru has an idea of what might be 
> wrong here, or can tell me where to continue troubleshooting :)

I'll put it bluntly, I don't think anyone's interested in
troubleshooting v3.14 anymore. Please try v4.5.

BR,
Jani.


>
> I've uploaded a kernel log (drm.debug=0xe) here: 
> http://pastebin.com/nYNRGW5B
>
> The video kernel parameter for this log is: video=LVDS-1:1920x1080. I've 
> tried others, M and/or R suffixes, loading edid/1920x1080.bin etc, but 
> nothing works. I'm not sure if all this EDID timing stuff is even used 
> for LVDS..
>
> One line in the log mentions a mode that is promising:
>
>    [    5.534021] [drm:intel_dump_crtc_timings], crtc timings: 148571 
> 1920 2040 2080 2200 1080 1097 1108 1125, type: 0x0 flags: 0xa
>
> In the BIOS, the panel type is configured as "1920x1080@148.5M", so that 
> looks good. I have no idea where that modeline came from though.
>
>  From what I can see, LVDS-1 and CRTC 3 are connected, but when it's 
> time to set the mode, it seems to have been modified into a bogus 
> adjusted mode:
>
>    [    5.570523] [drm:intel_dump_pipe_config], requested mode:
>    [    5.570525] [drm:drm_mode_debug_printmodeline], Modeline 
> 0:"1920x1080" 0 172780 1920 2040 2248 2576 1080 1081 1084 1118 0x0 0x6
>    [    5.570526] [drm:intel_dump_pipe_config], adjusted mode:
>    [    5.570529] [drm:drm_mode_debug_printmodeline], Modeline 
> 0:"640x480" 0 148571 640 656 752 800 480 490 492 525 0x8 0x0
>    [    5.570531] [drm:intel_dump_crtc_timings], crtc timings: 148571 
> 640 656 752 800 480 490 492 525, type: 0x8 flags: 0x0
>
> Also, the dot-clock mentioned in the HD mode is now 172780, for some 
> reason..
>
> All sorts of kernel warnings follow, after this (what is LVDS-6?):
>
>    [    5.570569] [drm:intel_crtc_mode_set], [ENCODER:6:LVDS-6] set 
> [MODE:0:1920x1080]
>
> Please let me know if you'd like more logging or details.
>
> Cheers,
>
>       Rob
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

-- 
Jani Nikula, Intel Open Source Technology Center
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

  reply	other threads:[~2016-04-01  8:01 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-01  4:49 Troubleshooting LVDS on GM45 Rob Kramer
2016-04-01  8:01 ` Jani Nikula [this message]
2016-04-01  8:11   ` Rob Kramer
2016-04-01 10:07 ` Troubleshooting LVDS on GM45 (kernel 4.5.0) Rob Kramer
2016-04-01 11:11   ` Jani Nikula
2016-04-04  3:14     ` Rob Kramer
2016-04-04 14:58       ` Ville Syrjälä
2016-04-05  4:07         ` Rob Kramer
2016-04-01 15:37 ` [PATCH 1/2] drm/i915: Read timings from the correct transcoder in intel_crtc_mode_get() ville.syrjala
2016-04-01 15:37   ` [PATCH 2/2] drm/i915: Use intel_get_pipe_timings() and intel_mode_from_pipe_config() " ville.syrjala
2016-04-01 18:48     ` [PATCH v2 " ville.syrjala
2016-04-13 12:08       ` Ville Syrjälä
2017-09-25 19:19       ` Chris Wilson
2017-10-09 16:18         ` Ville Syrjälä
2017-10-09 16:24           ` Chris Wilson
2017-10-09 16:48             ` Ville Syrjälä
2017-09-25 14:18   ` [Intel-gfx] [PATCH 1/2] drm/i915: Read timings from the correct transcoder " Chris Wilson
2016-04-01 16:44 ` ✗ Fi.CI.BAT: warning for series starting with [1/2] " Patchwork
2016-04-01 17:14   ` Ville Syrjälä

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