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<base href="https://bugs.freedesktop.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - libGL error: MESA-LOADER: failed to retrieve device information on virgl"
href="https://bugs.freedesktop.org/show_bug.cgi?id=107309">107309</a>
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<th>Summary</th>
<td>libGL error: MESA-LOADER: failed to retrieve device information on virgl
</td>
</tr>
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<th>Product</th>
<td>DRI
</td>
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<th>Version</th>
<td>XOrg git
</td>
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<th>Hardware</th>
<td>Other
</td>
</tr>
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<th>OS</th>
<td>All
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>medium
</td>
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<th>Component</th>
<td>libdrm
</td>
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<th>Assignee</th>
<td>dri-devel@lists.freedesktop.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>vliaskovitis@suse.com
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=140732" name="attach_140732" title="xf86drm: Correctly parse pci device information for virtio gpu">attachment 140732</a> <a href="attachment.cgi?id=140732&action=edit" title="xf86drm: Correctly parse pci device information for virtio gpu">[details]</a></span> <a href='page.cgi?id=splinter.html&bug=107309&attachment=140732'>[review]</a>
xf86drm: Correctly parse pci device information for virtio gpu
Mesa 18.1.3-201.1
kernel 4.17.5-1-default
libdrm 2.4.92-1.2
glxinfo | grep -i renderer
OpenGL renderer string: virgl
LIBGL_DEBUG=verbose glxgears
libGL error: MESA-LOADER: failed to retrieve device information
libGL: using driver virtio_gpu for 4
libGL: OpenDriver: trying /usr/lib64/dri/tls/virtio_gpu_dri.so
libGL: OpenDriver: trying /usr/lib64/dri/virtio_gpu_dri.so
Adding some debug drmMsg() prints, I found that the MESA-LOADER error message
happens because drmGetDevice2() returns -ENODEV. And that happens because
drmParseSubsystemType() returns -EINVAL.
drmParseSubsystemType() expects /sys/dev/char/DRM_MAJOR\:0/device/subsystem to
be one of pci, usb, platform, hostix. But virtio-gpu has bus subsystem virtio:
ls -al /sys/dev/char/226\:0/device/subsystem
lrwxrwxrwx 1 root root 0 Jul 19 17:39 /sys/dev/char/226:0/device/subsystem ->
../../../../bus/virtio
ls -al /sys/dev/char/226\:128/device/subsystem
lrwxrwxrwx 1 root root 0 Jul 19 17:39 /sys/dev/char/226:128/device/subsystem ->
../../../../bus/virtio
I am not sure if this is a cosmetic error, or if it matters. I am attaching a
proposed patch.
Since the virtio-gpu device is actually a pci device, we can still parse the
correct information from the corresponding pci device:
ls -al /sys/dev/char/226\:0
lrwxrwxrwx 1 root root 0 Jul 20 13:30 /sys/dev/char/226:0 ->
../../devices/pci0000:00/0000:00:02.0/virtio0/drm/card0
i.e. use /sys/dev/char/226\:128/../../../ instead of /sys/dev/char/226\:128/
for virtio devices.
to parse subsystem, and subsequently pci bus and pci device information.
(Let me know if bugzilla is still the place to report bugs, or if
<a href="https://gitlab.freedesktop.org/mesa/drm">https://gitlab.freedesktop.org/mesa/drm</a> is now the preferred location)</pre>
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