2016-07-14 10:22:16

by Colin King

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

From: Colin Ian King <[email protected]>

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 <[email protected]>
---
drivers/staging/rtl8723au/hal/rtl8723a_bt-coexist.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

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;
--
2.8.1

2016-07-20 11:36:07

by Jes Sorensen

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

Colin King <[email protected]> writes:
> From: Colin Ian King <[email protected]>
>
> 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 <[email protected]>
> ---
> 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;