On 2021-06-25 06:25, Bart Van Assche wrote:
On 6/23/21 7:23 PM, Can Guo wrote:
On 2021-06-24 05:51, Bart Van Assche wrote:
On 6/23/21 12:35 AM, Can Guo wrote:
- During system suspend, user space software is paused before the
device
driver freeze callbacks are invoked. Hence, the
hba->is_sys_suspended
check can be left out.
is_sys_suspended indicates that system resume failed (power/clk is
OFF).
- If a LUN is runtime suspended, it should be resumed if accessed
from
user space instead of failing user space accesses. In other words,
the
hba->is_wlu_sys_suspended check seems inappropriate to me.
hba->is_wlu_sys_suspended indicates that wl system resume failed,
device
is not operational.
Hi Can,
Thanks for the clarification. How about converting the above two
answers
into comments inside ufshcd_is_user_access_allowed()?
Sure.
Should ufshcd_is_user_access_allowed() perhaps be called after
ufshcd_rpm_get_sync() instead of before to prevent that the value of
hba->is_sys_suspended or hba->is_wlu_sys_suspended changes after having
been checked and before the UFS device is accessed?
is_sys_suspended and is_wlu_sys_suspended only represent system PM
status,
not runtime PM status.
My understanding is that user threads are frozen before system PM
starts,
so it does not matter we call ufshcd_is_user_access_allowed() before or
after ufshcd_rpm_get_sync().
If my understanding is wrong, then we need to either call
lock_system_sleep()
in get_user_access() or wrap
ufshcd_suspend_prepare/ufshcd_resume_complete()
with host_sem.
Thanks,
Can Guo.
Thanks,
Bart.
