linux-kernel - Re: [PATCH v2 3/4] spi: spi-geni-qcom: Don't try to set CS if an xfer is pending

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Message-ID: <160825991289.1580929.8225600641746583053@swboyd.mtv.corp.google.com>
Date:   Thu, 17 Dec 2020 18:51:52 -0800
From:   Stephen Boyd <swboyd@...omium.org>
To:     Doug Anderson <dianders@...omium.org>
Cc:     Mark Brown <broonie@...nel.org>, msavaliy@....qualcomm.com,
        Akash Asthana <akashast@...eaurora.org>,
        Roja Rani Yarubandi <rojay@...eaurora.org>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        linux-spi <linux-spi@...r.kernel.org>
Subject: Re: [PATCH v2 3/4] spi: spi-geni-qcom: Don't try to set CS if an xfer is pending

Quoting Doug Anderson (2020-12-17 13:35:08)
> 
> If we wanted to truly make this driver super robust against ridiculous
> interrupt latencies then, presumably, we could handle the SPI timeout
> ourselves but before timing out we could check to see if the
> interrupts were pending.  Then we could disable our interrupts,
> synchronize our interrupt handler, handle the interrupt directly, and
> then re-enable interrupts.  If we did this then transfers could
> continue to eek their way through even if interrupts were completely
> blocked.  IMO, it's not worth it.  I'm satisfied with not crashing and
> not getting the state machine too out-of-whack.
> 

Ok that's fair. If it's not worth the effort then let's drop this idea.