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References: <20191225120002.11163-1-wgong@codeaurora.org> <20191225120002.11163-3-wgong@codeaurora.org>
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From:   Justin Capella <justincapella@gmail.com>
Date:   Wed, 25 Dec 2019 14:56:01 -0800
Message-ID: <CAMrEMU9ZVV-yotvH2Odn+sb1HiiL_tN_GASSeSnhAOzCUjLZ7Q@mail.gmail.com>
Subject: Re: [PATCH v2 2/2] ath10k: start recovery process when payload length
 exceeds max htc length for sdio
To:     Wen Gong <wgong@codeaurora.org>
Cc:     ath10k <ath10k@lists.infradead.org>, linux-wireless@vger.kernel.org
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Sender: linux-wireless-owner@vger.kernel.org
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Does the SDIO bus require addresses to be word aligned like the PCI
bus does? I'm thinking of how netdev alloc uses skb_push to ensure
that the payload is aligned.


>> if (ar->state == ATH10K_STATE_ON)

What about the other STATEs: RESTARTED/ING

The value you mentioned 57005, is 0xDEAD is that a special case?
Perhaps a result of fw crash? Maybe a lookahead gone wong? I see its
the WMI PEER ALIVE/DEAD indicator but I'm not sure why it would be
trailer of the other

On Wed, Dec 25, 2019 at 4:01 AM Wen Gong <wgong@codeaurora.org> wrote:
>
> When simulate random transfer fail for sdio write and read, it happened
> "payload length exceeds max htc length" and recovery later sometimes.
>
> Test steps:
> 1. Add config and update kernel:
> CONFIG_FAIL_MMC_REQUEST=y
> CONFIG_FAULT_INJECTION=y
> CONFIG_FAULT_INJECTION_DEBUG_FS=y
>
> 2. Run simulate fail:
> cd /sys/kernel/debug/mmc1/fail_mmc_request
> echo 10 > probability
> echo 10 > times # repeat until hitting issues
>
> 3. It happened payload length exceeds max htc length.
> [  199.935506] ath10k_sdio mmc1:0001:1: payload length 57005 exceeds max htc length: 4088
> ....
> [  264.990191] ath10k_sdio mmc1:0001:1: payload length 57005 exceeds max htc length: 4088
>
> 4. after some time, such as 60 seconds, it start recovery which triggered
> by wmi command timeout for periodic scan.
> [  269.229232] ieee80211 phy0: Hardware restart was requested
> [  269.734693] ath10k_sdio mmc1:0001:1: device successfully recovered
>
> The simulate fail of sdio is not a real sdio transter fail, it only
> set an error status in mmc_should_fail_request after the transfer end,
> actually the transfer is success, then sdio_io_rw_ext_helper will
> return error status and stop transfer the left data. For example,
> the really RX len is 286 bytes, then it will split to 2 blocks in
> sdio_io_rw_ext_helper, one is 256 bytes, left is 30 bytes, if the
> first 256 bytes get an error status by mmc_should_fail_request,then
> the left 30 bytes will not read in this RX operation. Then when the
> next RX arrive, the left 30 bytes will be considered as the header
> of the read, the top 4 bytes of the 30 bytes will be considered as
> lookaheads, but actually the 4 bytes is not the lookaheads, so the len
> from this lookaheads is not correct, it exceeds max htc length 4088
> sometimes. When happened exceeds, the buffer chain is not matched between
> firmware and ath10k, then it need to start recovery ASAP. Recently then
> recovery will be started by wmi command timeout, but it will be long time
> later, for example, it is 60+ seconds later from the periodic scan, if
> it does not have periodic scan, it will be longer.
>
> Start recovery when it happened "payload length exceeds max htc length"
> will be reasonable.
>
> This patch only effect sdio chips.
>
> Tested with QCA6174 SDIO with firmware WLAN.RMH.4.4.1-00029.
>
> Signed-off-by: Wen Gong <wgong@codeaurora.org>
> ---
>  drivers/net/wireless/ath/ath10k/sdio.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/drivers/net/wireless/ath/ath10k/sdio.c b/drivers/net/wireless/ath/ath10k/sdio.c
> index 7b894dcaad2e..78f431609493 100644
> --- a/drivers/net/wireless/ath/ath10k/sdio.c
> +++ b/drivers/net/wireless/ath/ath10k/sdio.c
> @@ -557,6 +557,12 @@ static int ath10k_sdio_mbox_rx_alloc(struct ath10k *ar,
>                                     le16_to_cpu(htc_hdr->len),
>                                     ATH10K_HTC_MBOX_MAX_PAYLOAD_LENGTH);
>                         ret = -ENOMEM;
> +
> +                       if (ar->state == ATH10K_STATE_ON) {
> +                               queue_work(ar->workqueue, &ar->restart_work);
> +                               ath10k_warn(ar, "exceeds length, start recovery\n");
> +                       }
> +
>                         goto err;
>                 }
>
> --
> 2.23.0