On Fri, Nov 20, 2020 at 12:37:22AM -0800, Can Guo wrote:
> Runtime resume is handled by runtime PM framework, no need to forcibly
> set runtime PM status to RPM_ACTIVE during system resume/thaw/restore.
Sorry, I don't understand this explanation at all.
Sure, runtime resume is handled by the runtime PM framework. But this
patch changes the code for system resume, which is completely different.
Following a system resume, the hardware will be at full power. We don't
want the kernel to think that the device is still in runtime suspend;
otherwise is would never put the device back into low-power mode.
Alan Stern
> Cc: Stanley Chu <stanley.chu@xxxxxxxxxxxx>
> Cc: Bart Van Assche <bvanassche@xxxxxxx>
> Cc: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Can Guo <cang@xxxxxxxxxxxxxx>
> ---
>
> Changes since v1:
> - Incorporated Bart's comments
>
> ---
> drivers/scsi/scsi_pm.c | 24 +-----------------------
> 1 file changed, 1 insertion(+), 23 deletions(-)
>
> diff --git a/drivers/scsi/scsi_pm.c b/drivers/scsi/scsi_pm.c
> index 3717eea..908f27f 100644
> --- a/drivers/scsi/scsi_pm.c
> +++ b/drivers/scsi/scsi_pm.c
> @@ -79,25 +79,6 @@ static int scsi_dev_type_resume(struct device *dev,
> scsi_device_resume(to_scsi_device(dev));
> dev_dbg(dev, "scsi resume: %d\n", err);
>
> - if (err == 0) {
> - pm_runtime_disable(dev);
> - err = pm_runtime_set_active(dev);
> - pm_runtime_enable(dev);
> -
> - /*
> - * Forcibly set runtime PM status of request queue to "active"
> - * to make sure we can again get requests from the queue
> - * (see also blk_pm_peek_request()).
> - *
> - * The resume hook will correct runtime PM status of the disk.
> - */
> - if (!err && scsi_is_sdev_device(dev)) {
> - struct scsi_device *sdev = to_scsi_device(dev);
> -
> - blk_set_runtime_active(sdev->request_queue);
> - }
> - }
> -
> return err;
> }
>
> @@ -165,11 +146,8 @@ static int scsi_bus_resume_common(struct device *dev,
> */
> if (strncmp(scsi_scan_type, "async", 5) != 0)
> async_synchronize_full_domain(&scsi_sd_pm_domain);
> - } else {
> - pm_runtime_disable(dev);
> - pm_runtime_set_active(dev);
> - pm_runtime_enable(dev);
> }
> +
> return 0;
> }
>
> --
> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.
>
