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    <body><span class="vcard"><a class="email" href="mailto:lucas@lucas-nussbaum.net" title="Lucas Nussbaum <lucas@lucas-nussbaum.net>"> <span class="fn">Lucas Nussbaum</span></a>
</span> changed
              <a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - [hsw ult dp-to-vga] embedded DP-to-VGA output only works once"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=88590">bug 88590</a>
          <br>
             <table border="1" cellspacing="0" cellpadding="8">
          <tr>
            <th>What</th>
            <th>Removed</th>
            <th>Added</th>
          </tr>

         <tr>
           <td style="text-align:right;">Status</td>
           <td>NEEDINFO
           </td>
           <td>NEW
           </td>
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      <p>
        <div>
            <b><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - [hsw ult dp-to-vga] embedded DP-to-VGA output only works once"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=88590#c9">Comment # 9</a>
              on <a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - [hsw ult dp-to-vga] embedded DP-to-VGA output only works once"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=88590">bug 88590</a>
              from <span class="vcard"><a class="email" href="mailto:lucas@lucas-nussbaum.net" title="Lucas Nussbaum <lucas@lucas-nussbaum.net>"> <span class="fn">Lucas Nussbaum</span></a>
</span></b>
        <pre>(In reply to Jani Nikula from <a href="show_bug.cgi?id=88590#c8">comment #8</a>)
<span class="quote">> Please try v3.19-rc1 or later, or try cherry-picking

> commit 19a93f042fc241ecdf98543cedfe7c171f8cdf53
> Author: Dave Airlie <<a href="mailto:airlied@redhat.com">airlied@redhat.com</a>>
> Date:   Wed Nov 26 13:13:09 2014 +1000

>     drm/dp: retry AUX transactions 32 times (v1.1)

> to v3.18. The above commit is marked cc: stable, so it should eventually get
> backported to stable kernels. It should give the DP downstream a little more
> slack in responding; the legacy analog things may need that.</span >

Hi,

I tried with 3.19.0-rc5, and the problem still occurs. I'm adding the dmesg
output with drm.debug=0x06

Some more information:
There are two Ubuntu bug reports where users complain about the same problem
(or at least some of the
posters do -- others are commenting about seemingly unrelated issues)
<a href="https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1300914">https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1300914</a>
<a href="https://bugs.launchpad.net/ubuntu/+source/libdrm/+bug/1411552">https://bugs.launchpad.net/ubuntu/+source/libdrm/+bug/1411552</a>

<a href="show_bug.cgi?id=88590#c13">Comment 13</a> describes exactly the behaviour I'm seeing:
<a href="https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1300914/comments/13">https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1300914/comments/13</a>

Changing window manager (from GNOME to OpenBox) changes the behaviour:
- with OpenBox, switching to a TTY and then switching back to X "fixes"
  the problem.
- with GNOME, it does not.

However, I confirm that suspending/resuming "fixes" the problem (even with 
GNOME).</pre>
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