mac80211: fix sign error in pid controller

While testing the pid rate controller in mac80211_hwsim, I noticed
that once the controller reached 54 Mbit rates, it would fail to
lower the rate when necessary.  The debug log shows:

1945 186786 pf_sample 50 3534 3577 50

My interpretation is that the fixed point scaling of the target
error value (pf) is incorrect: the error value of 50 compared to
a target of 14 case should result in a scaling value of
(14-50) = -36 * 256 or -9216, but instead it is (14 * 256)-50, or
3534.

Correct this by doing fixed point scaling after subtraction.

Signed-off-by: Bob Copeland <[email protected]>
Acked-by: Stefano Brivio <[email protected]>
Acked-by: Mattias Nissler <[email protected]>
Signed-off-by: John W. Linville <[email protected]>

0 files changed, 0 insertions, 0 deletions