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<base href="https://bugs.freedesktop.org/" />
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<body><table border="1" cellspacing="0" cellpadding="8">
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<th>Priority</th>
<td>medium
</td>
</tr>
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - drm/i915: VGA cannot be turned on"
href="https://bugs.freedesktop.org/show_bug.cgi?id=77137">77137</a>
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</tr>
<tr>
<th>CC</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr>
<tr>
<th>Assignee</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr>
<tr>
<th>Summary</th>
<td>drm/i915: VGA cannot be turned on
</td>
</tr>
<tr>
<th>QA Contact</th>
<td>intel-gfx-bugs@lists.freedesktop.org
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr>
<tr>
<th>OS</th>
<td>Linux (All)
</td>
</tr>
<tr>
<th>Reporter</th>
<td>bugs-freedesktop-ugeuder@snkmail.com
</td>
</tr>
<tr>
<th>Hardware</th>
<td>x86 (IA32)
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Version</th>
<td>DRI CVS
</td>
</tr>
<tr>
<th>Component</th>
<td>DRM/Intel
</td>
</tr>
<tr>
<th>Product</th>
<td>DRI
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=97039" name="attach_97039" title="kernel log for mode switch on VGA">attachment 97039</a> <a href="attachment.cgi?id=97039&action=edit" title="kernel log for mode switch on VGA">[details]</a></span>
kernel log for mode switch on VGA
When trying to turn on VGA output using command
xrandr --output VGA1 --mode 800x600
nothing happens. (Expected result: VGA display turned on)
This was first observed using a 3.11 distro kernel, but it is 100% repeatable
using the 3.14 mainline kernel and also the drm-intel-next/2014-04-05-trusty
kernel from the Ubuntu kernel team.
Observation: Changing mode on LVDS1 is successful, but a kernel warning is
produced.
[ 87.540325] [drm:intel_pipe_config_compare] *ERROR* mismatch in
gmch_pfit.lvds_border_bits (expected 32768, found 0)
[ 87.540334] ------------[ cut here ]------------
[ 87.540441] WARNING: CPU: 1 PID: 934 at
/home/apw/COD/linux/drivers/gpu/drm/i915/intel_display.c:9813
check_crtc_state+0x26b/0x360 [i915]()
[ 87.540447] pipe state doesn't match!
I don't know whether the warning for LVDS1 is in any way related to
non-functional VGA. For LVDS1 everything seems to work fine but a kernel
warning is produced. For VGA1 nothing visible works, but no warning is produced
either.
Attached kernel log dmesg-994-vga.txt has been produced the following way
1.) Boot kernel drm-intel-next/2014-04-05-trusty as built by Ubuntu kernel team
with extra command line parameter drm.debug=0x
2.) attach VGA display
3.) run script
#!/bin/sh
cmd="xrandr --output VGA1 --mode 800x600"
echo "*** calling $cmd" | sudo tee /dev/kmsg
$cmd
echo "*** returned from $cmd" | sudo tee /dev/kmsg
Attached kernel log dmesg-994-lvds.txt has been produced the following way
1.) Boot kernel drm-intel-next/2014-04-05-trusty as built by Ubuntu kernel team
with extra command line parameter drm.debug=0x
2.) run script
#!/bin/sh
cmd="xrandr --output LVDS1 --mode 800x600"
echo "*** calling $cmd" | sudo tee /dev/kmsg
$cmd
echo "*** returned from $cmd" | sudo tee /dev/kmsg</pre>
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