[Bug 78795] New: BayTrail [DP to LVDS] No signal from LVDS

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=78795

          Priority: medium
            Bug ID: 78795
                CC: intel-gfx-bugs at lists.freedesktop.org
          Assignee: intel-gfx-bugs at lists.freedesktop.org
           Summary: BayTrail [DP to LVDS] No signal from LVDS
        QA Contact: intel-gfx-bugs at lists.freedesktop.org
          Severity: critical
    Classification: Unclassified
                OS: Linux (All)
          Reporter: dominikr at aaeon.com
          Hardware: x86-64 (AMD64)
            Status: NEW
           Version: unspecified
         Component: DRM/Intel
           Product: DRI

HI All:

I work for AAEON an Asus company who makes embedded, long life, motherboards. I
am running into a situation with a large customer of mine that wants to use a
15.6" LCD Panel,
https://dl.dropboxusercontent.com/u/52392/TFT-LCD%2BPreliminary%2BSpecification%2BG156BGE-L01%2Bver%2B1.0.pdf
 connected to the EMB-BT1 with the n2807 SOC, I have also tried the E3825/E3845
series and have the same issue,
https://dl.dropboxusercontent.com/u/52392/EMB-BT1.pdf connected via the LVDS
Connector. AAEON takes the eDP port and runs it through a Chrontel CH7511,
http://www.chrontel.com/media/Datasheets/CH7511B%20Brief%20Datasheet%20V1.13.pdf
chip to convert it to the LVDS Signal.

The issue I am having is when LVDS is only connected and the system boots up I
do not get a picture on the LCD Panel. Once I kill power to the board and
connect a HDMI or VGA connection the board boots up with Ubuntu 14.04. I am
able to boot into the BIOS and check all the settings but once I leave the BIOS
and Ubuntu tries to start up I get a white screen on the LCD Panel. Here is a
video I took: https://dl.dropboxusercontent.com/u/52392/LVDS.mp4  I have been
trying to load the daily and drm-intel-nightly builds of the latest kernel but
this issue still comes up. I have even tried today's build of 2014-05-15.

I know this is something with the Linux Kernel because when I load up Windows 8
I get a picture automatically every time without this white screen. I also have
tried Timesys 18 Fedora Remix Image:
https://dl.dropboxusercontent.com/u/52392/GettingStarted_Timesys18FedoraRemix.pdf
and I do not experience this issue.

The system still boots and I can ssh into it. I installed today's latest kernel
2014-05-16 and here is the dmesg: http://pastebin.com/F59jdUF4

Please contact me if you have any questions or things to try. My contact is in
my signature below. Thank you for looking at this issue.

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