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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 - eglQueryDevicesEXT returns 0 devices"
href="https://bugs.freedesktop.org/show_bug.cgi?id=103575">103575</a>
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<th>Summary</th>
<td>eglQueryDevicesEXT returns 0 devices
</td>
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<th>Product</th>
<td>Mesa
</td>
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<th>Version</th>
<td>17.2
</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>normal
</td>
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<th>Priority</th>
<td>medium
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<th>Component</th>
<td>Drivers/Gallium/r600
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<th>Assignee</th>
<td>dri-devel@lists.freedesktop.org
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<th>Reporter</th>
<td>Hi-Angel@yandex.ru
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<th>QA Contact</th>
<td>dri-devel@lists.freedesktop.org
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<p>
<div>
<pre>I'm following this guide
<a href="https://devblogs.nvidia.com/parallelforall/egl-eye-opengl-visualization-without-x-server/">https://devblogs.nvidia.com/parallelforall/egl-eye-opengl-visualization-without-x-server/</a>
to choose a GPU through native means of EGL.
Using eglQueryDevicesEXT() in both modes, i.e. with "devices" array to get
descriptions, as well as by passing 0 as "devices", results in 0 as a number of
supported devices. Specification says that I should've get at least 1 (and I
actually have two, r600g-managed, cards):
<a href="https://www.khronos.org/registry/EGL/extensions/EXT/EGL_EXT_device_enumeration.txt">https://www.khronos.org/registry/EGL/extensions/EXT/EGL_EXT_device_enumeration.txt</a>
<span class="quote">> EGL devices can be enumerated before EGL is initialized. Use:
>
> EGLBoolean eglQueryDevicesEXT(EGLint max_devices,
> EGLDeviceEXT *devices,
> EGLint *num_devices);</span >
[SNIP]
<span class="quote">> If <devices> is NULL, then <max_devices> will be ignored, no devices will be
> returned in <devices>, and <num_devices> will be set to the number of
> supported devices in the system. All implementations must support at least
> one device.
>
> On failure, EGL_FALSE is returned.</span >
Below is the modified code I'm using:
#include <EGL/egl.h>
#include <EGL/eglext.h>
#include <stdio.h>
int main(int argc, char *argv[])
{
EGLint numDevices;
PFNEGLQUERYDEVICESEXTPROC eglQueryDevicesEXT =
(PFNEGLQUERYDEVICESEXTPROC)
eglGetProcAddress("eglQueryDevicesEXT");
if (eglQueryDevicesEXT(2, 0, &numDevices) == EGL_FALSE) {
puts("error in eglQueryDevicesEXT");
return 1;
}
printf("Detected %d devices\n", numDevices);
}</pre>
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