[Intel-gfx] [PATCH i-g-t] tests/kms_frontbuffer_tracking: Correctly handle debugfs errors

[Michal Wajdeczko]

In commit 3f6ae7b19 ("igt/kms_frontbuffer_tracking: Keep the debugfs
dir around") we introduced custom variant of __igt_debugfs_read function
that fires assert when debugfs returns an error. Replace that assert
with proper error handling to allow use of errors like -ENODEV.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko at intel.com>
Cc: Chris Wilson <chris at chris-wilson.co.uk>
---
 tests/kms_frontbuffer_tracking.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tests/kms_frontbuffer_tracking.c b/tests/kms_frontbuffer_tracking.c
index a068c8a..50019d1 100644
--- a/tests/kms_frontbuffer_tracking.c
+++ b/tests/kms_frontbuffer_tracking.c
@@ -783,7 +783,8 @@ static bool set_mode_for_params(struct modeset_params *params)
 static void __debugfs_read(const char *param, char *buf, int len)
 {
 	len = igt_sysfs_read(drm.debugfs, param, buf, len - 1);
-	igt_assert(len > 0);
+	if (len < 0)
+		len = 0;
 	buf[len] = '\0';
 }
 
-- 
2.7.4