linux-kernel - Re: [PACTH v3] mmc: sdhci: Do not allow tuning procedure to be interrupted

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Message-ID: <0c1a3043-9ed1-9d01-0f07-231d6ece874f@collabora.com>
Date:	Wed, 17 Aug 2016 13:31:16 -0400
From:	Robert Foss <robert.foss@...labora.com>
To:	Adrian Hunter <adrian.hunter@...el.com>, ulf.hansson@...aro.org,
	linux-mmc@...r.kernel.org, linux-kernel@...r.kernel.org,
	Andrew Bresticker <abrestic@...omium.org>,
	Kevin Cernekee <cernekee@...omium.org>,
	Benson Leung <bleung@...omium.org>,
	Christopher Freeman <cfreeman@...dia.com>
Subject: Re: [PACTH v3] mmc: sdhci: Do not allow tuning procedure to be
 interrupted



On 2016-08-17 06:47 AM, Adrian Hunter wrote:
> On 17/08/16 00:25, robert.foss@...labora.com wrote:
>> From: Christopher Freeman <cfreeman@...dia.com>
>>
>> wait_event_interruptible_timeout() will return early if the blocked
>> process receives a signal, causing the driver to abort the tuning
>> procedure and possibly leaving the controller in a bad state.  Since the
>> tuning command is expected to complete quickly (<50ms) and we've set a
>> timeout, use wait_event_timeout() instead.
>>
>> Signed-off-by: Christopher Freeman <cfreeman@...dia.com>
>> Tested-by: Robert Foss <robert.foss@...labora.com>
>> Signed-off-by: Robert Foss <robert.foss@...labora.com>
>> Reviewed-by: Benson Leung <bleung@...omium.org>
>
> The mmc block queues are kernel threads which I would expect ignore signals,
> so I am curious how you hit this?

The issue was discovered on (tegra2?) hardware that is sensitive to 
being interrupted during tuning and having the controller left in a 
sensitive state.

@Christopher Freeman: Maybe you can provide us with some additional details?

>
> In any case:
>
> Acked-by: Adrian Hunter <adrian.hunter@...el.com>
>