Prefer i830_dri.so for gen2 chipsets

Probe for i830_dri.so and, if it exists, use that driver in preference
to i915_dri.so for DRI (i.e. GL clients). This was suggested in the
context of distributions supplying i915g as the main DRI driver for
gen3, in which case we need to provide a separate DRI driver for gen2.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

Makefile.am

@@ -18,7 +18,7 @@
 #  IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 #  CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
-ACLOCAL_AMFLAGS = ${ACLOCAL_FLAGS}
+ACLOCAL_AMFLAGS = ${ACLOCAL_FLAGS} -I m4
 
 SUBDIRS = man
 

configure.ac

@@ -28,6 +28,7 @@ AC_INIT([xf86-video-intel],
         [xf86-video-intel])
 AC_CONFIG_SRCDIR([Makefile.am])
 AC_CONFIG_HEADERS([config.h])
+AC_CONFIG_MACRO_DIR([m4])
 AC_CONFIG_AUX_DIR(.)
 
 # Initialize Automake
@@ -168,6 +169,8 @@ AC_ARG_WITH(xorg-module-dir,
 
 AC_ARG_ENABLE(dri, AS_HELP_STRING([--disable-dri],
                                   [Disable DRI support [[default=auto]]]))
+dridriverdir=`$PKG_CONFIG --variable=dridriverdir dri`
+AC_DEFINE_DIR(DRI_DRIVER_PATH, dridriverdir, [Default DRI driver path])
 
 AC_ARG_ENABLE(xvmc, AS_HELP_STRING([--disable-xvmc],
                                   [Disable XvMC support [[default=yes]]]),

m4/ac_define_dir.m4

@@ -0,0 +1,49 @@
+# ===========================================================================
+#             http://autoconf-archive.cryp.to/ac_define_dir.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AC_DEFINE_DIR(VARNAME, DIR [, DESCRIPTION])
+#
+# DESCRIPTION
+#
+#   This macro sets VARNAME to the expansion of the DIR variable, taking
+#   care of fixing up ${prefix} and such.
+#
+#   VARNAME is then offered as both an output variable and a C preprocessor
+#   symbol.
+#
+#   Example:
+#
+#      AC_DEFINE_DIR([DATADIR], [datadir], [Where data are placed to.])
+#
+# LAST MODIFICATION
+#
+#   2008-04-12
+#
+# COPYLEFT
+#
+#   Copyright (c) 2008 Stepan Kasal <kasal@ucw.cz>
+#   Copyright (c) 2008 Andreas Schwab <schwab@suse.de>
+#   Copyright (c) 2008 Guido U. Draheim <guidod@gmx.de>
+#   Copyright (c) 2008 Alexandre Oliva
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved.
+
+AC_DEFUN([AC_DEFINE_DIR], [
+  prefix_NONE=
+  exec_prefix_NONE=
+  test "x$prefix" = xNONE && prefix_NONE=yes && prefix=$ac_default_prefix
+  test "x$exec_prefix" = xNONE && exec_prefix_NONE=yes && exec_prefix=$prefix
+dnl In Autoconf 2.60, ${datadir} refers to ${datarootdir}, which in turn
+dnl refers to ${prefix}.  Thus we have to use `eval' twice.
+  eval ac_define_dir="\"[$]$2\""
+  eval ac_define_dir="\"$ac_define_dir\""
+  AC_SUBST($1, "$ac_define_dir")
+  AC_DEFINE_UNQUOTED($1, "$ac_define_dir", [$3])
+  test "$prefix_NONE" && prefix=NONE
+  test "$exec_prefix_NONE" && exec_prefix=NONE
+])

src/intel_dri.c

@@ -1523,13 +1523,24 @@ out_complete:
 static int dri2_server_generation;
 #endif
 
+static bool has_i830_dri(void)
+{
+	return access(DRI_DRIVER_PATH "/i830_dri.so", R_OK) == 0;
+}
+
 static const char *dri_driver_name(intel_screen_private *intel)
 {
 	const char *s = xf86GetOptValString(intel->Options, OPTION_DRI);
 	Bool dummy;
 
-	if (s == NULL || xf86getBoolValue(&dummy, s))
-		return INTEL_INFO(intel)->gen < 040 ? "i915" : "i965";
+	if (s == NULL || xf86getBoolValue(&dummy, s)) {
+		if (INTEL_INFO(intel)->gen < 030)
+			return has_i830_dri() ? "i830" : "i915";
+		else if (INTEL_INFO(intel)->gen < 040)
+			return "i915";
+		else
+			return "i965";
+	}
 
 	return s;
 }

src/sna/sna_dri.c

@@ -39,6 +39,7 @@ USE OR OTHER DEALINGS IN THE SOFTWARE.
 #include <errno.h>
 #include <time.h>
 #include <string.h>
+#include <unistd.h>
 
 #include "sna.h"
 #include "sna_reg.h"
@@ -2381,13 +2382,24 @@ out_complete:
 }
 #endif
 
+static bool has_i830_dri(void)
+{
+	return access(DRI_DRIVER_PATH "/i830_dri.so", R_OK) == 0;
+}
+
 static const char *dri_driver_name(struct sna *sna)
 {
 	const char *s = xf86GetOptValString(sna->Options, OPTION_DRI);
 	Bool dummy;
 
-	if (s == NULL || xf86getBoolValue(&dummy, s))
-		return sna->kgem.gen < 040 ? "i915" : "i965";
+	if (s == NULL || xf86getBoolValue(&dummy, s)) {
+		if (sna->kgem.gen < 030)
+			return has_i830_dri() ? "i830" : "i915";
+		else if (sna->kgem.gen < 040)
+			return "i915";
+		else
+			return "i965";
+	}
 
 	return s;
 }