linux-kernel - Re: [PATCH v6] platform/chrome: cros_ec: Query EC protocol version if EC transitions between RO/RW

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Message-ID: <8a4273cc-3700-8398-598e-cbcb05e6e595@collabora.com>
Date:   Tue, 11 Feb 2020 10:42:17 +0100
From:   Enric Balletbo i Serra <enric.balletbo@...labora.com>
To:     Yicheng Li <yichengli@...omium.org>,
        LKML <linux-kernel@...r.kernel.org>
Cc:     bleung@...omium.org, groeck@...omium.org, lee.jones@...aro.org,
        gwendal@...omium.org, andriy.shevchenko@...ux.intel.com,
        Jonathan.Cameron@...wei.com, evgreen@...omium.org,
        rushikesh.s.kadam@...el.com, tglx@...utronix.de
Subject: Re: [PATCH v6] platform/chrome: cros_ec: Query EC protocol version if
 EC transitions between RO/RW


On 3/2/20 23:53, Yicheng Li wrote:
> RO and RW of EC may have different EC protocol version. If EC transitions
> between RO and RW, but AP does not reboot (this is true for fingerprint
> microcontroller / cros_fp, but not true for main ec / cros_ec), the AP
> still uses the protocol version queried before transition, which can
> cause problems. In the case of fingerprint microcontroller, this causes
> AP to send the wrong version of EC_CMD_GET_NEXT_EVENT to RO in the
> interrupt handler, which in turn prevents RO to clear the interrupt
> line to AP, in an infinite loop.
> 
> Once an EC_HOST_EVENT_INTERFACE_READY is received, we know that there
> might have been a transition between RO and RW, so re-query the protocol.
> 
> Signed-off-by: Yicheng Li <yichengli@...omium.org>
> ---

Queued for 5.7 with all the collected tags, thanks.