How to build mesa

Foreword

Mesa is a special package since many flavours are built, which means it takes quite some time to get all packages ready, as well as some disc space (over 2GB for the build/ directory alone).

Also, trying to figure out whether latest master is also affected, or backporting some bug fixes might lead to some painful I/O while generating the .deb files, and then installing/unpacking them. This is why this document was written: Helping users test other mesa releases, branches, bug fixes without having to build full packages, and without having to mess with their systems (i.e. no root access is needed once the build dependencies are installed).

We’ll focus on the DRI (Direct Rendering Infrastructure) flavour (libgl1-mesa-dri), which is the most common.

It might be possible to adapt the following steps to another flavour, in which case the appropriate options to be passed to ./configure should be looked up in the debian/rules file of the Debian source package.

Gathering information

Get started by installing mesa-utils, which contains glxinfo.

Is direct rendering enabled?

$ glxinfo | grep ^direct
direct rendering: Yes

↪ Yes.

Is this the classic or Gallium driver?

$ glxinfo | grep 'renderer string'
OpenGL renderer string: Mesa DRI Intel(R) 945GM GEM 20100330 DEVELOPMENT

↪ No “Gallium” here, therefore: “classic”.

Which driver is this, and where is it located?

$ LIBGL_DEBUG=verbose glxinfo 2>&1 >/dev/null | grep so$
libGL: OpenDriver: trying /usr/lib/dri/tls/i915_dri.so
libGL: OpenDriver: trying /usr/lib/dri/i915_dri.so

↪ i915, from the system directory: /usr/lib/dri (likely installed through a Debian package).

How can I get more debugging information?

export LIBGL_DEBUG=verbose
export MESA_DEBUG=1
export EGL_LOG_LEVEL=debug

Preparing mesa sources

To get started, installing all build dependencies of the mesa source package should be sufficient, along with the essential build tools, and git:

$ sudo apt-get install build-essential git
$ sudo apt-get build-dep mesa

Make sure you have some disc space available, since the git repository is over 120MB, and since the mesa directory is over 500MB after a build. Once you’re ready, grab the upstream mesa sources:

$ git clone git://anongit.freedesktop.org/mesa/mesa mesa.git
$ cd mesa.git
$ autoreconf -vfi

Here’s what the ./configure call will look like:

$ ./configure --prefix=/usr \
              --enable-driglx-direct \
              --enable-gles1 \
              --enable-gles2 \
              --enable-glx-tls \
              --with-dri-driverdir=/usr/lib/dri \
              --with-egl-platforms='drm x11' \
              …

Now, what are the parameters to replace “…” with? Basically, if you determined an Intel driver (i915 or i965), you want to use the classic drivers and to disable the Gallium drivers. Other drivers are only available on Gallium (r300, r600, radeonsi and more). Running ./configure --help might be useful.

Examples for common drivers:

For i915, you need:
```
--with-dri-drivers=i915
```
For i965, you need:
```
--with-dri-drivers=i965
```

For nouveau, you may want to try:

--with-dri-drivers=nouveau --with-gallium-drivers=nouveau

For r300, you need:
```
--with-gallium-drivers=r300
```
For r600, you need:
```
--with-gallium-drivers=r600
```
For radeonsi, you need:
```
--with-gallium-drivers=radeonsi
```

Now, once you’ve run ./configure, time for your favorite beverage:

$ make

Running the newly-built mesa libraries

Shared libraries end up in the lib/ directory. It contains the classic drivers, while Gallium drivers end up under lib/gallium. If you’re not an Intel user, overwrite the classic drivers with the Gallium ones:

$ mv lib/gallium/* lib/

Now, 3 variables need to be set, so that the locally-built libraries are used.

To begin with, libGL itself and its drivers:

$ export LIBGL_DRIVERS_PATH=lib

Did this work?

$ LIBGL_DEBUG=verbose glxinfo 2>&1 >/dev/null | grep so$
libGL: OpenDriver: trying lib/tls/i915_dri.so
libGL: OpenDriver: trying lib/i915_dri.so

↪ Yes: No system directory, paths are relative to lib/.

Set LD_LIBRARY_PATH to make sure the locally-built libraries (including those pulled through library dependencies) are used, instead of system ones:
```
$ export LD_LIBRARY_PATH=lib
```
Did this work?
```
$ ldd lib/libGLESv2.so | grep glapi
    libglapi.so.0 => lib/libglapi.so.0 (0x00007fee3192e000)
```
↪ Yes: Path is relative to lib.

Set the EGL search path:

$ export EGL_DRIVERS_PATH=lib/egl