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Message-ID: <c0d4a3e8-3130-48a6-88d6-75156c4147d9@gmail.com>
Date: Tue, 2 Jan 2024 14:22:08 +0200
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Subject: Re: [PATCH] wifi: rtl8xxxu: Fix off by one initial RTS rate
To: Ping-Ke Shih <pkshih@realtek.com>,
 "linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>
Cc: Jes Sorensen <Jes.Sorensen@gmail.com>
References: <be0427a7-f85f-449e-a6c8-b1c8371c39b0@gmail.com>
 <f8aaaf712d6940d48a05ae3d33aa25be@realtek.com>
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From: Bitterblue Smith <rtl8821cerfe2@gmail.com>
In-Reply-To: <f8aaaf712d6940d48a05ae3d33aa25be@realtek.com>
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On 02/01/2024 02:45, Ping-Ke Shih wrote:
> 
> 
>> -----Original Message-----
>> From: Bitterblue Smith <rtl8821cerfe2@gmail.com>
>> Sent: Monday, January 1, 2024 6:19 AM
>> To: linux-wireless@vger.kernel.org
>> Cc: Jes Sorensen <Jes.Sorensen@gmail.com>; Ping-Ke Shih <pkshih@realtek.com>
>> Subject: [PATCH] wifi: rtl8xxxu: Fix off by one initial RTS rate
>>
>> rtl8xxxu_set_basic_rates() sets the wrong initial RTS rate. It sets the
>> next higher rate than the one it should set, e.g. 36M instead of 24M.
>>
>> The while loop is supposed to find the index of the most significant
>> bit which is 1.
>>
>> Signed-off-by: Bitterblue Smith <rtl8821cerfe2@gmail.com>
>> ---
>>  drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
>> b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
>> index 180907319e8c..b9f3382bd67c 100644
>> --- a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
>> +++ b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
>> @@ -4839,7 +4839,7 @@ static void rtl8xxxu_set_basic_rates(struct rtl8xxxu_priv *priv, u32 rate_cfg)
>>
>>         dev_dbg(&priv->udev->dev, "%s: rates %08x\n", __func__, rate_cfg);
>>
>> -       while (rate_cfg) {
>> +       while (rate_cfg > 1) {
>>                 rate_cfg = (rate_cfg >> 1);
>>                 rate_idx++;
>>         }
> 
> How about using __fls()? 
> 
> if (rate_cfg)
> 	rate_idx = __fls(rate_cfg);
> 
Yes, that's nicer.