linux-kernel - Re: [PATCH] ath10k: Wait until copy complete is actually done before completing

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Date:   Mon, 15 Jun 2020 17:56:19 +0300
From:   Kalle Valo <kvalo@...eaurora.org>
To:     Doug Anderson <dianders@...omium.org>
Cc:     Sai Prakash Ranjan <saiprakash.ranjan@...eaurora.org>,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        linux-wireless <linux-wireless@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>, ath10k@...ts.infradead.org,
        Rakesh Pillai <pillair@...eaurora.org>,
        netdev <netdev@...r.kernel.org>,
        Jakub Kicinski <kuba@...nel.org>,
        "David S. Miller" <davem@...emloft.net>, kuabhs@...gle.com
Subject: Re: [PATCH] ath10k: Wait until copy complete is actually done before completing

Doug Anderson <dianders@...omium.org> writes:

> On Mon, Jun 15, 2020 at 7:32 AM Kalle Valo <kvalo@...eaurora.org> wrote:
>>
>> Douglas Anderson <dianders@...omium.org> wrote:
>>
>> > On wcn3990 we have "per_ce_irq = true".  That makes the
>> > ath10k_ce_interrupt_summary() function always return 0xfff. The
>> > ath10k_ce_per_engine_service_any() function will see this and think
>> > that _all_ copy engines have an interrupt.  Without checking, the
>> > ath10k_ce_per_engine_service() assumes that if it's called that the
>> > "copy complete" (cc) interrupt fired.  This combination seems bad.
>> >
>> > Let's add a check to make sure that the "copy complete" interrupt
>> > actually fired in ath10k_ce_per_engine_service().
>> >
>> > This might fix a hard-to-reproduce failure where it appears that the
>> > copy complete handlers run before the copy is really complete.
>> > Specifically a symptom was that we were seeing this on a Qualcomm
>> > sc7180 board:
>> >   arm-smmu 15000000.iommu: Unhandled context fault:
>> >   fsr=0x402, iova=0x7fdd45780, fsynr=0x30003, cbfrsynra=0xc1, cb=10
>> >
>> > Even on platforms that don't have wcn3990 this still seems like it
>> > would be a sane thing to do.  Specifically the current IRQ handler
>> > comments indicate that there might be other misc interrupt sources
>> > firing that need to be cleared.  If one of those sources was the one
>> > that caused the IRQ handler to be called it would also be important to
>> > double-check that the interrupt we cared about actually fired.
>> >
>> > Signed-off-by: Douglas Anderson <dianders@...omium.org>
>> > Signed-off-by: Kalle Valo <kvalo@...eaurora.org>
>>
>> ath10k firmwares work very differently, on what hardware and firmware did you
>> test this? I'll add that information to the commit log.
>
> I am running on a Qualcomm sc7180 SoC.

Sorry, I was unclear, I meant the ath10k hardware :) I guess WCN3990 but
what firmware version?

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