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

From: Kalle Valo <kvalo@codeaurora.org>
To: Douglas Anderson <dianders@chromium.org>
Cc: saiprakash.ranjan@codeaurora.org, linux-arm-msm@vger.kernel.org,
	linux-wireless@vger.kernel.org, ath10k@lists.infradead.org,
	linux-kernel@vger.kernel.org, pillair@codeaurora.org,
	netdev@vger.kernel.org, Jakub Kicinski <kuba@kernel.org>,
	"David S. Miller" <davem@davemloft.net>,
	kuabhs@google.com
Subject: Re: [PATCH] ath10k: Wait until copy complete is actually done before completing
Date: Mon, 15 Jun 2020 14:32:37 +0000 (UTC)	[thread overview]
Message-ID: <20200615143237.5A57BC433CB@smtp.codeaurora.org> (raw)
In-Reply-To: <20200609082015.1.Ife398994e5a0a6830e4d4a16306ef36e0144e7ba@changeid>

Douglas Anderson <dianders@chromium.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@chromium.org>
> Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

ath10k firmwares work very differently, on what hardware and firmware did you
test this? I'll add that information to the commit log.

-- 
https://patchwork.kernel.org/patch/11595887/

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

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