igt/drv_module_reload: Check more carefully for a live driver

As drm_open_any() now quietly fails if there is no driver, this
nullifies the effectiviness of using gem_exec_nop as the test for a good
reload. Combine with gem_alive (and guarantee that gem_alive can detect
a dead driver, putting lie to

commit 032f30cb38bb03562ee7fde19cd278b1d8ac31a9
Author: Thomas Wood <thomas.wood@intel.com>
Date:   Tue Jan 13 13:33:57 2015 +0000

    lib: remove unnecessary checks on the drm_open_any return value

) first.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=88573
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

lib/drmtest.c

@@ -224,7 +224,7 @@ int drm_get_card(void)
 }
 
 /** Open the first DRM device we can find, searching up to 16 device nodes */
-static int __drm_open_any(void)
+int __drm_open_any(void)
 {
 	for (int i = 0; i < 16; i++) {
 		char name[80];

lib/drmtest.h

@@ -71,6 +71,7 @@ static inline void *igt_mmap64(void *addr, size_t length, int prot, int flags,
 #define ALIGN(v, a) (((v) + (a)-1) & ~((a)-1))
 
 int drm_get_card(void);
+int __drm_open_any(void);
 int drm_open_any(void);
 int drm_open_any_master(void);
 int drm_open_any_render(void);

tests/drv_module_reload

@@ -43,7 +43,18 @@ echo 1 > /sys/class/vtconsole/vtcon1/bind
 
 modprobe snd_hda_intel
 
-# try to run something
-$SOURCE_DIR/gem_exec_nop > /dev/null && echo "module successfully loaded again"
+# does the device exist?
+if $SOURCE_DIR/gem_alive > /dev/null ; then
+	echo "module successfully loaded again"
+else
+	echo "failed to reload module successfully"
+	exit 2
+fi
+
+# then try to run something
+if ! $SOURCE_DIR/gem_exec_nop > /dev/null ; then
+	echo "failed to execute a simple batch after reload"
+	exit 3
+fi
 
 exit 0

tests/gem_alive.c

@@ -14,7 +14,9 @@ int main(void)
 
 	signal(SIGALRM, SIG_IGN);
 
-	fd = drm_open_any();
+	fd = __drm_open_any();
+	if (fd < 0)
+		return IGT_EXIT_SKIP;
 
 	alarm(1);
 	if (ioctl(fd, DRM_IOCTL_I915_GEM_SW_FINISH, &arg) == 0)