[PATCH v2] scsi: ufs: Avoid runtime suspend possibly being blocked forever

Avri Altman Avri.Altman at wdc.com
Thu Jun 13 01:09:45 PDT 2019


> 
> UFS runtime suspend can be triggered after pm_runtime_enable()
> is invoked in ufshcd_pltfrm_init(). However if the first runtime
> suspend is triggered before binding ufs_hba structure to ufs
> device structure via platform_set_drvdata(), then UFS runtime
> suspend will be no longer triggered in the future because its
> dev->power.runtime_error was set in the first triggering and does
> not have any chance to be cleared.
> 
> To be more clear, dev->power.runtime_error is set if hba is NULL
> in ufshcd_runtime_suspend() which returns -EINVAL to rpm_callback()
> where dev->power.runtime_error is set as -EINVAL. In this case, any
> future rpm_suspend() for UFS device fails because
> rpm_check_suspend_allowed() fails due to non-zero
> dev->power.runtime_error.
> 
> To resolve this issue, make sure the first UFS runtime suspend
> get valid "hba" in ufshcd_runtime_suspend(): Enable UFS runtime PM
> only after hba is successfully bound to UFS device structure.
> 
> Fixes: 62694735ca95 ([SCSI] ufs: Add runtime PM support for UFS host
> controller driver)
> Cc: stable at vger.kernel.org
> Signed-off-by: Stanley Chu <stanley.chu at mediatek.com>
Reviewed-by: Avri Altman <avri.altman at wdc.com>




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