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Subject: Re: [PATCH wireless-next v2 1/4] wifi: rtw88: sdio: Check the HISR
 RX_REQUEST bit in rtw_sdio_rx_isr()
From:   Kalle Valo <kvalo@kernel.org>
In-Reply-To: <20230522202425.1827005-2-martin.blumenstingl@googlemail.com>
References: <20230522202425.1827005-2-martin.blumenstingl@googlemail.com>
To:     Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Cc:     linux-wireless@vger.kernel.org, linux-mmc@vger.kernel.org,
        linux-kernel@vger.kernel.org, ulf.hansson@linaro.org,
        tony0620emma@gmail.com, Peter Robinson <pbrobinson@gmail.com>,
        Ping-Ke Shih <pkshih@realtek.com>, jernej.skrabec@gmail.com,
        Larry Finger <Larry.Finger@lwfinger.net>,
        Martin Blumenstingl <martin.blumenstingl@googlemail.com>
User-Agent: pwcli/0.1.1-git (https://github.com/kvalo/pwcli/) Python/3.7.3
Message-ID: <168503099830.22756.1444846830853755949.kvalo@kernel.org>
Date:   Thu, 25 May 2023 16:10:00 +0000 (UTC)
Precedence: bulk

Martin Blumenstingl <martin.blumenstingl@googlemail.com> wrote:

> rtw_sdio_rx_isr() is responsible for receiving data from the wifi chip
> and is called from the SDIO interrupt handler when the interrupt status
> register (HISR) has the RX_REQUEST bit set. After the first batch of
> data has been processed by the driver the wifi chip may have more data
> ready to be read, which is managed by a loop in rtw_sdio_rx_isr().
> 
> It turns out that there are cases where the RX buffer length (from the
> REG_SDIO_RX0_REQ_LEN register) does not match the data we receive. The
> following two cases were observed with a RTL8723DS card:
> - RX length is smaller than the total packet length including overhead
>   and actual data bytes (whose length is part of the buffer we read from
>   the wifi chip and is stored in rtw_rx_pkt_stat.pkt_len). This can
>   result in errors like:
>     skbuff: skb_over_panic: text:ffff8000011924ac len:3341 put:3341
>   (one case observed was: RX buffer length = 1536 bytes but
>    rtw_rx_pkt_stat.pkt_len = 1546 bytes, this is not valid as it means
>    we need to read beyond the end of the buffer)
> - RX length looks valid but rtw_rx_pkt_stat.pkt_len is zero
> 
> Check if the RX_REQUEST is set in the HISR register for each iteration
> inside rtw_sdio_rx_isr(). This mimics what the RTL8723DS vendor driver
> does and makes the driver only read more data if the RX_REQUEST bit is
> set (which seems to be a way for the card's hardware or firmware to
> tell the host that data is ready to be processed).
> 
> For RTW_WCPU_11AC chips this check is not needed. The RTL8822BS vendor
> driver for example states that this check is unnecessary (but still uses
> it) and the RTL8822CS drops this check entirely.
> 
> Reviewed-by: Ping-Ke Shih <pkshih@realtek.com>
> Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>

4 patches applied to wireless-next.git, thanks.

e967229ead0e wifi: rtw88: sdio: Check the HISR RX_REQUEST bit in rtw_sdio_rx_isr()
9be20a822327 wifi: rtw88: rtw8723d: Implement RTL8723DS (SDIO) efuse parsing
09fcdbd28404 mmc: sdio: Add/rename SDIO ID of the RTL8723DS SDIO wifi cards
a3b125ceb45e wifi: rtw88: Add support for the SDIO based RTL8723DS chipset

-- 
https://patchwork.kernel.org/project/linux-wireless/patch/20230522202425.1827005-2-martin.blumenstingl@googlemail.com/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches