Re: [PATCH] staging: rtl8723au: hal: check BT_Active and BT_State with correct bit pattern

From: Jes Sorensen
Date: Wed Jul 20 2016 - 07:36:22 EST


Colin King <colin.king@xxxxxxxxxxxxx> writes:
> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>
> BT_Active and BT_State are being masked with 0x00ffffff so it the subsequent
> comparisons with 0xffffffff are therefore a buggy check. Instead, check them
> against 0x00ffffff.
>
> Unfortunately I couldn't find a datasheet or hardware to see if 0xffffffff
> is an expected invalid bit pattern that should be checked before BT_Active and
> BT_State are masked with 0x00ffffff, so for now, this fix seems like the least
> risky approach.
>
> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> ---
> drivers/staging/rtl8723au/hal/rtl8723a_bt-coexist.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)

I don't really know about the BT parts here, since I never did anything
with that part of the chip. Larry probably knows more.

The only question is whether fixing this bug changes behavior that has
unexpected side effects?

Cheers,
Jes

>
> diff --git a/drivers/staging/rtl8723au/hal/rtl8723a_bt-coexist.c b/drivers/staging/rtl8723au/hal/rtl8723a_bt-coexist.c
> index bfcbd7a..6989580 100644
> --- a/drivers/staging/rtl8723au/hal/rtl8723a_bt-coexist.c
> +++ b/drivers/staging/rtl8723au/hal/rtl8723a_bt-coexist.c
> @@ -9824,7 +9824,7 @@ void BTDM_CheckBTIdleChange1Ant(struct rtw_adapter *padapter)
> BT_Polling = rtl8723au_read32(padapter, regBTPolling);
> RTPRINT(FBT, BT_TRACE, ("[DM][BT], BT_Polling(0x%x) =%x\n", regBTPolling, BT_Polling));
>
> - if (BT_Active == 0xffffffff && BT_State == 0xffffffff && BT_Polling == 0xffffffff)
> + if (BT_Active == 0x00ffffff && BT_State == 0x00ffffff && BT_Polling == 0xffffffff)
> return;
> if (BT_Polling == 0)
> return;