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Message-ID: <ef4555a6-1674-d9c0-6401-cdf43780a014@windriver.com>
Date: Fri, 9 Apr 2021 09:33:30 +0800
From: "quanyang.wang" <quanyang.wang@...driver.com>
To: Michal Simek <michal.simek@...inx.com>,
Dinghao Liu <dinghao.liu@....edu.cn>, kjlu@....edu,
Amit Kumar Mahapatra <amit.kumar-mahapatra@...inx.com>
Cc: Mark Brown <broonie@...nel.org>, linux-spi@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] spi: spi-zynqmp-gqspi: Fix runtime PM imbalance in
zynqmp_qspi_probe
Hi Dinghao,
On 4/8/21 6:33 PM, Michal Simek wrote:
> ++
>
> On 4/8/21 11:25 AM, Dinghao Liu wrote:
>> When platform_get_irq() fails, a pairing PM usage counter
>> increment is needed to keep the counter balanced. It's the
>> same for the following error paths.
>>
>> Signed-off-by: Dinghao Liu <dinghao.liu@....edu.cn>
>> ---
>> drivers/spi/spi-zynqmp-gqspi.c | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/spi/spi-zynqmp-gqspi.c b/drivers/spi/spi-zynqmp-gqspi.c
>> index c8fa6ee18ae7..95963a2de64a 100644
>> --- a/drivers/spi/spi-zynqmp-gqspi.c
>> +++ b/drivers/spi/spi-zynqmp-gqspi.c
>> @@ -1197,6 +1197,7 @@ static int zynqmp_qspi_probe(struct platform_device *pdev)
>> return 0;
>>
>> clk_dis_all:
>> + pm_runtime_get_noresume(&pdev->dev);
>> pm_runtime_set_suspended(&pdev->dev);
>> pm_runtime_disable(&pdev->dev);
>> clk_disable_unprepare(xqspi->refclk);
>>
The imbalance is because pm_runtime_put_autosuspend is called to make
counter to be -1.
It looks strange that there is no counter increament op before
pm_runtime_put_autosuspend.
In my limited understanding, it should look like:
......
pm_runtime_enable
pm_runtime_get_sync //increase counter to one to resume device
DO OPERATIONS HERE
pm_runtime_mark_last_busy
pm_runtime_put_autosuspend //decrease counter to zero and trigger suspend
return 0;
error_path:
pm_runtime_put_sync
pm_runtime_disable
return err;
Am I missing something?
Thanks,
Quanyang
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