[Bug 40699] New: KMS on Thinkpad W500: no picture on external monitors with DisplayPort, but DVI works.

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=40699

           Summary: KMS on Thinkpad W500: no picture on external monitors
                    with DisplayPort, but DVI works.
           Product: DRI
           Version: XOrg CVS
          Platform: x86-64 (AMD64)
        OS/Version: Linux (All)
            Status: NEW
          Severity: normal
          Priority: medium
         Component: DRM/Radeon
        AssignedTo: dri-devel at lists.freedesktop.org
        ReportedBy: andreas.wallberg at gmail.com


Hi all!

I have troubles connecting my Thinkpad W500 running Arch Linux 64-bit to
external monitors via DisplayPort (DP) while using Kernel Mode Setting (KMS)
and a recent kernel (3.0.4). KMS + DP appears to be broken. The laptop has a
ATI Radeon HD 3650 chip.

I have tried two monitors: the HP ZR22w and the Eizo EV2333W.

HP ZR22w
========

When KMS+DP is used on boot, I get this error message on the HP ZR22w:

    Input signal Out of Range
    Change Settings to 1920 x 1080 - 60Hz


Inside X11, I am unable to get the screen going when KMS+DP is used. xrandr
reports the screen being connected and that 1920x1080 is being sent to it. I
still have the same error message.

If I turn off KMS, the monitor works just fine with DP and X11 and xrandr do
their jobs but I obviously lose all the niceties with KMS.

If I use a DP->DVI adaptor and instead use the DVI connector on the monitor,
KMS works just fine.

However, using the 2.6.35 kernel in Fedora 14, KMS + DP works just fine.

Eizo EV2333W
============

The same behavior as reported for the HP is true on the Eizo EV2333W monitor,
but the latter provides more informative dialogs.

Using the old Fedora 2.6.35 kernel and KMS+DP, the monitor shows this info
about the video signal on the Information dialog:

DisplayPort
1920x1080
fH: 76.5kHz
fV: 59.9Hz

Using a 3.0.4 kernel in Arch and KMS+DP, the monitor shows:

Signal Error
DisplayPort
fD: 111.1MHz
fH: 50.5kHz
fV: 44.8Hz

The "44.8" on the last line is read so there is obviously something wrong with
the signal here.

My guess is that the EDID handling is broken somehow on DP. I have tried adding
various video= switches in grub to force the resolution but I am not really
sure how apply them to the DisplayPort (unable to find any documentation on
this) or whether it matters since the problem seems to be that the kernel is
unaware it sends an incorrect video signal to the monitor.

The only reference I have found to this monitor and KMS is this one, but I am
not sure what to make of it:
http://www.spinics.net/lists/dri-devel/msg13061.html

I would much appreciate any pointers! What logs and config files would you like
to follow up on this?

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