UBI: fix tests

This patch fixes UBI tests and adds udev problems solution description.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/ubi-utils/tests/README.udev b/ubi-utils/tests/README.udev
new file mode 100644
index 0000000..a4ff9c5
--- /dev/null
+++ b/ubi-utils/tests/README.udev
@@ -0,0 +1,19 @@
+There is a problem with udev: when a volume is created, there is a delay
+before corresponding /dev/ubiX_Y device node is created by udev, so some
+tests fail because of this. The symptom is error messages like
+"cannot open /dev/ubi0_0".
+
+One possible solution of this problem is to pre-create UBI device and volume
+nodes. there is even a script which may be used for this in ubi-utils/scripts/.
+But this is not enough because udev will still remove and re-create the nodes
+and tests will still fail. So you need to stop removing device nodes using
+the following udev rule:
+
+	KERNEL=="ubi*_*", ACTION=="remove", OPTIONS+="ignore_device"
+
+In our Ubuntu distribution we put that to new file:
+/etc/udev/rules.d/50-local.rules
+
+Another possibility is to call udevsettle utility in libubi after the volume
+has been created See src/libubi.c - the call is there but is commented out.
+This is anyway an ugly hack, but works, although makes the tests slower.