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Subject: Re: [PATCH 2/2] wcn36xx: fix RX BD rate mapping for 5GHz legacy rates
To:     Bryan O'Donoghue <bryan.odonoghue@linaro.org>,
        Kalle Valo <kvalo@codeaurora.org>
Cc:     Loic Poulain <loic.poulain@linaro.org>,
        linux-arm-msm@vger.kernel.org,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>, wcn36xx@lists.infradead.org,
        linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <20211028223131.897548-1-benl@squareup.com>
 <20211028223131.897548-2-benl@squareup.com>
 <b3473977-5bb6-06df-55c3-85f08a29a964@linaro.org>
From:   Benjamin Li <benl@squareup.com>
Message-ID: <631a3ab4-56d9-5c1d-be53-c885747e3f7b@squareup.com>
Date:   Thu, 28 Oct 2021 17:39:58 -0700
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On 10/28/21 5:30 PM, Bryan O'Donoghue wrote:
> On 28/10/2021 23:31, Benjamin Li wrote:
>> -            status.rate_idx >= sband->n_bitrates) {
> This fix was applied because we were getting a negative index
> 
> If you want to remove that, you'll need to do something about this
> 
> status.rate_idx -= 4;

Hmm... so you're saying there's a FW bug where sometimes we get
bd->rate_id = 0-7 (leading to status.rate_idx = 0-3) on a 5GHz
channel?

static const struct wcn36xx_rate wcn36xx_rate_table[] = {
    /* 11b rates */
    {  10, 0, RX_ENC_LEGACY, 0, RATE_INFO_BW_20 },
    {  20, 1, RX_ENC_LEGACY, 0, RATE_INFO_BW_20 },
    {  55, 2, RX_ENC_LEGACY, 0, RATE_INFO_BW_20 },
    { 110, 3, RX_ENC_LEGACY, 0, RATE_INFO_BW_20 },

    /* 11b SP (short preamble) */
    {  10, 0, RX_ENC_LEGACY, RX_ENC_FLAG_SHORTPRE, RATE_INFO_BW_20 },
    {  20, 1, RX_ENC_LEGACY, RX_ENC_FLAG_SHORTPRE, RATE_INFO_BW_20 },
    {  55, 2, RX_ENC_LEGACY, RX_ENC_FLAG_SHORTPRE, RATE_INFO_BW_20 },
    { 110, 3, RX_ENC_LEGACY, RX_ENC_FLAG_SHORTPRE, RATE_INFO_BW_20 },

It sounds like we should WARN and drop the frame in that case. If
you agree I'll send a v2.

> 
> ---
> bod