Hi Avri, On Wed, 2019-06-12 at 11:10 +0000, Avri Altman wrote: > Hi, > > > > > 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: e3ce73d (scsi: ufs: fix bugs related to null pointer access and array size) > This code was inserted before platform_set_drvdata in > 6269473 [SCSI] ufs: Add runtime PM support for UFS host controller driver. > Why do you point to e3ce73d? e3ce73d (scsi: ufs: fix bugs related to null pointer access and array size) changed the returned value from 0 to -EINVAL in case of NULL "hba" in ufshcd_runtime_suspend(). But you are right, above patch may do the right thing, and the real root cause is the incorrect timing of pm_runtime_enable(). I will fix commit message in next version. > > Thanks, > Avri Thanks. Stanley
