drm/i915: fix error path in intel_setup_gmbus()

commit ed3f9fd1e865975ceefdb2a43b453e090b1fd787 upstream.

This fails to undo the setup for pin==0; moreover, something
interesting happens if the setup failed already at pin==0.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Fixes: f899fc64cda8 ("drm/i915: use GMBUS to manage i2c links")
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1455048677-19882-3-git-send-email-linux@rasmusvillemoes.dk
(cherry picked from commit 2417c8c03f508841b85bf61acc91836b7b0e2560)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
[bwh: Backported to 3.2: index variable is i, not pin]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/gpu/drm/i915/intel_i2c.c b/drivers/gpu/drm/i915/intel_i2c.c
index d30cccc..e035eaf 100644 (file)
--- a/drivers/gpu/drm/i915/intel_i2c.c
+++ b/drivers/gpu/drm/i915/intel_i2c.c
@@ -410,7 +410,7 @@ int intel_setup_gmbus(struct drm_device *dev)
        return 0;
 
 err:
-       while (--i) {
+       while (i--) {
                struct intel_gmbus *bus = &dev_priv->gmbus[i];
                i2c_del_adapter(&bus->adapter);
        }