[igt-dev] [PATCH i-g-t] Make force work with multiple drivers available

[Rodrigo Siqueira]

The force option allows users to specify which driver they want that IGT
uses. Nonetheless, if the user has two or more loaded drivers in his
system, the force option will not work as expected because IGT will take
the first driver found at /dev/dri. This problem can be reproduced in a
QEMU VM that using Bochs and VKMS. This patch handles this scenario by
ensuring that IGT uses the forced module specified via IGT_FORCE_DRIVER.

Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo at gmail.com>
---
 lib/drmtest.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/lib/drmtest.c b/lib/drmtest.c
index 35914c50..7c124ac6 100644
--- a/lib/drmtest.c
+++ b/lib/drmtest.c
@@ -250,10 +250,8 @@ static int open_device(const char *name, unsigned int chipset)
 		goto err;
 
 	forced = forced_driver();
-	if (forced && chipset == DRIVER_ANY && !strcmp(forced, dev_name)) {
-		igt_debug("Force option used: Using driver %s\n", dev_name);
-		return fd;
-	}
+	if (forced && chipset == DRIVER_ANY && strcmp(forced, dev_name))
+		goto err;
 
 	for (int start = 0, end = ARRAY_SIZE(modules) - 1; start < end; ){
 		int mid = start + (end - start) / 2;
@@ -277,6 +275,12 @@ err:
 
 static int __search_and_open(const char *base, int offset, unsigned int chipset)
 {
+	const char *forced;
+
+	forced = forced_driver();
+	if (forced)
+		igt_info("Force option used: Using driver %s\n", forced);
+
 	for (int i = 0; i < 16; i++) {
 		char name[80];
 		int fd;
-- 
2.20.1