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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - gbm_bo_map fails on i915 when *map_data is not NULL before call"
href="https://bugs.freedesktop.org/show_bug.cgi?id=110855">110855</a>
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<th>Summary</th>
<td>gbm_bo_map fails on i915 when *map_data is not NULL before call
</td>
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<th>Product</th>
<td>Mesa
</td>
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<th>Version</th>
<td>19.0
</td>
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<th>Hardware</th>
<td>x86-64 (AMD64)
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<th>OS</th>
<td>Linux (All)
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>trivial
</td>
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<th>Priority</th>
<td>lowest
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<th>Component</th>
<td>Drivers/DRI/i965
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<th>Assignee</th>
<td>intel-3d-bugs@lists.freedesktop.org
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<th>Reporter</th>
<td>freebugs@mstoeckl.com
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<th>QA Contact</th>
<td>intel-3d-bugs@lists.freedesktop.org
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<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=144477" name="attach_144477" title="Test case, compile with gcc -lgbm">attachment 144477</a> <a href="attachment.cgi?id=144477&action=edit" title="Test case, compile with gcc -lgbm">[details]</a></span>
Test case, compile with gcc -lgbm
The documentation for the function gbm_bo_map in src/gbm/main/gbm.c states that
the argument void** map_data is a "Returned opaque ptr for the mapped region".
Contrary to convention for a return value, if *map_data is not NULL, and the
DRI i965 driver is used, then gbm_bo_map fails.
The value of *map_data is checked by intel_map_image in
src/mesa/drivers/dri/i965/intel_screen.c (line 823 in today's git master).
Debugging this (see attached test program) was made slightly more complicated
by the fact that errno was set to ENODEV, after the syscall
DRM_IOCTL_I915_GEM_CONTEXT_CREATE failed on the first call to gbm_bo_map .
Reading kernel sources implies that this probably only happens for <gen6 intel
GPUs.</pre>
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