On Fri, May 03, 2019 at 12:01:05PM +0000, Tony Chuang wrote: > > Subject: [RFC] rtw88: fix subscript above array bounds compiler warning > > > > My compiler complain about: > > > > drivers/net/wireless/realtek/rtw88/phy.c: In function > > ‘rtw_phy_rf_power_2_rssi’: > > drivers/net/wireless/realtek/rtw88/phy.c:430:26: warning: array subscript is > > above array bounds [-Warray-bounds] > > linear = db_invert_table[i][j]; > > > > According to comment power_db should be in range 1 ~ 96 . > > Correct rtw_phy_power_2_db() to make max power 96 db > > (still min is 0). This make the warning gone. > > > > However power >= 20 check still looks somewhat suspicious to me. > > > > Signed-off-by: Stanislaw Gruszka <[email protected]> > > --- > > drivers/net/wireless/realtek/rtw88/phy.c | 6 +++--- > > 1 file changed, 3 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/net/wireless/realtek/rtw88/phy.c > > b/drivers/net/wireless/realtek/rtw88/phy.c > > index 35a35dbca85f..a716a44d78b0 100644 > > --- a/drivers/net/wireless/realtek/rtw88/phy.c > > +++ b/drivers/net/wireless/realtek/rtw88/phy.c > > @@ -410,12 +410,12 @@ void rtw_phy_dynamic_mechanism(struct rtw_dev > > *rtwdev) > > > > static u8 rtw_phy_power_2_db(s8 power) > > { > > - if (power <= -100 || power >= 20) > > + if (power <= -96 || power >= 20) > > return 0; > > else if (power >= 0) > > - return 100; > > + return 96; > > else > > - return 100 + power; > > + return 96 + power; > > } > > > > static u64 rtw_phy_db_2_linear(u8 power_db) > > -- > > I think I should check with the radio team, that if the power from the > rx descriptor generated by hardware can possibly get >= 20 > > And also check what the actual logic they expected to deal with the power. > Thanks for reporting it.
Yeah, this could be just teoretical issue as we can not get power values >= 0 from HW. However I think compiler correctly complains, as for power_db=100 we get i = ((100 - 1) >> 3) = 12 , what exceed by one max first index of db_invert_table[][], which should be in range 0 - 11. Stanislaw
