linux-kernel - Re: [PATCH] Revert "dmaengine: dw: Enable runtime PM"

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Message-ID: <cdb0eaaf-5b00-e4af-29c9-2328fd23fbd2@intel.com>
Date:   Wed, 3 Feb 2021 20:21:33 +0100
From:   Cezary Rojewski <cezary.rojewski@...el.com>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     dmaengine <dmaengine@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Dan Williams <dan.j.williams@...el.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        viresh kumar <vireshk@...nel.org>,
        Vinod Koul <vkoul@...nel.org>
Subject: Re: [PATCH] Revert "dmaengine: dw: Enable runtime PM"

On 2021-02-03 6:06 PM, Andy Shevchenko wrote:
> On Wed, Feb 3, 2021 at 5:53 PM Cezary Rojewski
> <cezary.rojewski@...el.com> wrote:
>>
>> This reverts commit 842067940a3e3fc008a60fee388e000219b32632.
>> For some solutions e.g. sound/soc/intel/catpt, DW DMA is part of a
>> compound device (in that very example, domains: ADSP, SSP0, SSP1, DMA0
>> and DMA1 are part of a single entity) rather than being a standalone
>> one. Driver for said device may enlist DMA to transfer data during
>> suspend or resume sequences.
>>
>> Manipulating RPM explicitly in dw's DMA request and release channel
>> functions causes suspend() to also invoke resume() for the exact same
>> device. Similar situation occurs for resume() sequence. Effectively
>> renders device dysfunctional after first suspend() attempt. Revert the
>> change to address the problem.
> 
> I kinda had the mixed feelings about this, thanks for the report.
> Acked-by: Andy Shevchenko <andy.shevchenko@...il.com>
> 
> Fixes tag?

Noted, sent v2 with updated tag area.

Thanks,
Czarek