Hello:
This patch was applied to qcom/linux.git (refs/heads/for-next):
On Mon, 24 May 2021 12:03:12 +0800 you wrote:
> During system resume, MHI host triggers M3->M0 transition and then waits
> for target device to enter M0 state. Once done, the device queues a state
> change event into ctrl event ring and notifies MHI host by raising an
> interrupt, where a tasklet is scheduled to process this event. In most cases,
> the tasklet is served timely and wait operation succeeds.
>
> However, there are cases where CPU is busy and cannot serve this tasklet
> for some time. Once delay goes long enough, the device moves itself to M1
> state and also interrupts MHI host after inserting a new state change
> event to ctrl ring. Later CPU finally has time to process the ring, however
> there are two events in it now:
> 1. for M3->M0 event, which is processed first as queued first,
> tasklet handler updates device state to M0 and wakes up the task,
> i.e., the MHI host.
> 2. for M0->M1 event, which is processed later, tasklet handler
> triggers M1->M2 transition and updates device state to M2 directly,
> then wakes up the MHI host(if still sleeping on this wait queue).
> Note that although MHI host has been woken up while processing the first
> event, it may still has no chance to run before the second event is processed.
> In other words, MHI host has to keep waiting till timeout cause the M0 state
> has been missed.
>
> [...]
Here is the summary with links:
- [v2] bus: mhi: Wait for M2 state during system resume
https://git.kernel.org/qcom/c/02b49cd11745
You are awesome, thank you!
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