[Intel-gfx] [PATCH igt] igt/kms_fbcon_fbt: Handle ENODEV when checking i915_fbc_info for chipset support

[Chris Wilson]

If the machine doesn't support FBC, it will return -ENODEV from
i915_fbc_info, which we want to interpret as unsupported.

Reported-by: Marta Lofstedt<marta.lofstedt at intel.com>
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Reviewed-by: Marta Lofstedt<marta.lofstedt at intel.com>
---
 tests/kms_fbcon_fbt.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tests/kms_fbcon_fbt.c b/tests/kms_fbcon_fbt.c
index 51f11728..1b236f8b 100644
--- a/tests/kms_fbcon_fbt.c
+++ b/tests/kms_fbcon_fbt.c
@@ -87,6 +87,9 @@ static bool fbc_supported_on_chipset(int fd)
 	char buf[128];
 
 	igt_debugfs_read(fd, "i915_fbc_status", buf);
+	if (*buf == '\0') /* !HAS_FBC -> -ENODEV*/
+		return false;
+
 	return !strstr(buf, "FBC unsupported on this chipset\n");
 }
 
-- 
2.16.1