On 2/03/21 5:21 am, Asutosh Das wrote:

During runtime-suspend of ufs host, the scsi devices are
already suspended and so are the queues associated with them.
But the ufs host sends SSU to wlun during its runtime-suspend.
During the process blk_queue_enter checks if the queue is not in
suspended state. If so, it waits for the queue to resume, and never
comes out of it.
The commit
(d55d15a33: scsi: block: Do not accept any requests while suspended)
adds the check if the queue is in suspended state in blk_queue_enter().

Call trace:
 __switch_to+0x174/0x2c4
 __schedule+0x478/0x764
 schedule+0x9c/0xe0
 blk_queue_enter+0x158/0x228
 blk_mq_alloc_request+0x40/0xa4
 blk_get_request+0x2c/0x70
 __scsi_execute+0x60/0x1c4
 ufshcd_set_dev_pwr_mode+0x124/0x1e4
 ufshcd_suspend+0x208/0x83c
 ufshcd_runtime_suspend+0x40/0x154
 ufshcd_pltfrm_runtime_suspend+0x14/0x20
 pm_generic_runtime_suspend+0x28/0x3c
 __rpm_callback+0x80/0x2a4
 rpm_suspend+0x308/0x614
 rpm_idle+0x158/0x228
 pm_runtime_work+0x84/0xac
 process_one_work+0x1f0/0x470
 worker_thread+0x26c/0x4c8
 kthread+0x13c/0x320
 ret_from_fork+0x10/0x18

Fix this by registering ufs device wlun as a scsi driver and
registering it for block runtime-pm. Also make this as a
supplier for all other luns. That way, this device wlun
suspends after all the consumers and resumes after
hba resumes.

Co-developed-by: Can Guo <redacted>
Signed-off-by: Can Guo <redacted>
Signed-off-by: Asutosh Das <redacted>
---

Now we need either to move the suspend/resume vops from
ufshcd_suspend/resume to __ufshcd_wl_suspend/resume, assuming that
would work for existing implementations of those callbacks,
or otherwise create new vops ->wl_suspend() / ->wl_resume(), and
then split the existing implementations of those callbacks.

ufs_intel_resume() now needs to be invoked from __ufshcd_wl_resume().
I am not sure about the others:

	exynos_ufs_suspend()
	exynos_ufs_resume()
	ufs_hisi_suspend()
	ufs_hisi_resume()
	ufs_mtk_suspend()
	ufs_mtk_resume()
	ufs_qcom_suspend()
	ufs_qcom_resume()

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