From: Kalle Valo <kvalo@kernel.org>
To: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Cc: linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org,
jernej.skrabec@gmail.com, pkshih@realtek.com,
ulf.hansson@linaro.org, tony0620emma@gmail.com, lukas@mntre.com,
Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Subject: Re: [PATCH v3] wifi: rtw88: sdio: Honor the host max_req_size in the RX path
Date: Fri, 1 Dec 2023 12:40:36 +0000 (UTC) [thread overview]
Message-ID: <170143443423.2072551.2418172782235693510.kvalo@kernel.org> (raw)
In-Reply-To: <20231120115726.1569323-1-martin.blumenstingl@googlemail.com>
Martin Blumenstingl <martin.blumenstingl@googlemail.com> wrote:
> Lukas reports skb_over_panic errors on his Banana Pi BPI-CM4 which comes
> with an Amlogic A311D (G12B) SoC and a RTL8822CS SDIO wifi/Bluetooth
> combo card. The error he observed is identical to what has been fixed
> in commit e967229ead0e ("wifi: rtw88: sdio: Check the HISR RX_REQUEST
> bit in rtw_sdio_rx_isr()") but that commit didn't fix Lukas' problem.
>
> Lukas found that disabling or limiting RX aggregation works around the
> problem for some time (but does not fully fix it). In the following
> discussion a few key topics have been discussed which have an impact on
> this problem:
> - The Amlogic A311D (G12B) SoC has a hardware bug in the SDIO controller
> which prevents DMA transfers. Instead all transfers need to go through
> the controller SRAM which limits transfers to 1536 bytes
> - rtw88 chips don't split incoming (RX) packets, so if a big packet is
> received this is forwarded to the host in it's original form
> - rtw88 chips can do RX aggregation, meaning more multiple incoming
> packets can be pulled by the host from the card with one MMC/SDIO
> transfer. This Depends on settings in the REG_RXDMA_AGG_PG_TH
> register (BIT_RXDMA_AGG_PG_TH limits the number of packets that will
> be aggregated, BIT_DMA_AGG_TO_V1 configures a timeout for aggregation
> and BIT_EN_PRE_CALC makes the chip honor the limits more effectively)
>
> Use multiple consecutive reads in rtw_sdio_read_port() and limit the
> number of bytes which are copied by the host from the card in one
> MMC/SDIO transfer. This allows receiving a buffer that's larger than
> the hosts max_req_size (number of bytes which can be transferred in
> one MMC/SDIO transfer). As a result of this the skb_over_panic error
> is gone as the rtw88 driver is now able to receive more than 1536 bytes
> from the card (either because the incoming packet is larger than that
> or because multiple packets have been aggregated).
>
> In case of an receive errors (-EILSEQ has been observed by Lukas) we
> need to drain the remaining data from the card's buffer, otherwise the
> card will return corrupt data for the next rtw_sdio_read_port() call.
>
> Fixes: 65371a3f14e7 ("wifi: rtw88: sdio: Add HCI implementation for SDIO based chipsets")
> Reported-by: Lukas F. Hartmann <lukas@mntre.com>
> Closes: https://lore.kernel.org/linux-wireless/CAFBinCBaXtebixKbjkWKW_WXc5k=NdGNaGUjVE8NCPNxOhsb2g@mail.gmail.com/
> Suggested-by: Ping-Ke Shih <pkshih@realtek.com>
> Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
> Acked-by: Ping-Ke Shih <pkshih@realtek.com>
> Tested-by: Lukas F. Hartmann <lukas@mntre.com>
> Reported-by: Lukas F. Hartmann <lukas@mntre.com>
> Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
> Acked-by: Ping-Ke Shih <pkshih@realtek.com>
> Tested-by: Lukas F. Hartmann <lukas@mntre.com>
Patch applied to wireless-next.git, thanks.
00384f565a91 wifi: rtw88: sdio: Honor the host max_req_size in the RX path
--
https://patchwork.kernel.org/project/linux-wireless/patch/20231120115726.1569323-1-martin.blumenstingl@googlemail.com/
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
prev parent reply other threads:[~2023-12-01 12:40 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-20 11:57 [PATCH v3] wifi: rtw88: sdio: Honor the host max_req_size in the RX path Martin Blumenstingl
2023-11-21 12:24 ` Ulf Hansson
2023-11-22 0:47 ` Ping-Ke Shih
2023-11-30 19:13 ` Kalle Valo
[not found] ` <87edg7ujhi.fsf@mntre.com>
2023-12-01 0:33 ` Ping-Ke Shih
2023-12-01 6:31 ` Kalle Valo
2023-12-01 12:40 ` Kalle Valo [this message]
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