Commit d7dad550 authored Apr 14, 2013 by Emmanuel Grumbach Committed by Johannes Berg Apr 16, 2013

iwlwifi: mvm: fix first_antenna



first_antenna is supposed to return the first antenna as a
0-based bitmap: ANT_A is BIT(0), ANT_B is BIT(1), etc...
Since ffs is 1 based (ffs(BIT(0)) = 1), then we had an
off-by-one bug:
BIT(ffs(ANT_A)) = BIT(ffs(BIT(0))) = BIT(1) = ANT_B.
So what we really want is:
BIT(ffs(ANT_A) - 1) = BIT(ffs(BIT(0)) - 1) = BIT(0) = ANT_A.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

parent 178bdb57

drivers/net/wireless/iwlwifi/mvm/utils.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -253,8 +253,9 @@ int iwl_mvm_rx_fw_error(struct iwl_mvm mvm, struct iwl_rx_cmd_buffer rxb,
		u8 first_antenna(u8 mask)
		{
		BUILD_BUG_ON(ANT_A != BIT(0)); /* using ffs is wrong if not */
		WARN_ON_ONCE(!mask); /* ffs will return 0 if mask is zeroed */
		return (u8)(BIT(ffs(mask)));
		if (WARN_ON_ONCE(!mask)) /* ffs will return 0 if mask is zeroed */
		return BIT(0);
		return BIT(ffs(mask) - 1);
		}

		/*