On 07/03/2018 11:03 AM, Nc, Shreyas wrote:
+ struct sdw_master_runtime *m_rt, *_m_rt;
+
mutex_lock(&bus->bus_lock);
- sdw_release_master_stream(stream);
- sdw_master_port_release(bus, stream->m_rt);
- stream->state = SDW_STREAM_RELEASED;
- kfree(stream->m_rt);
- stream->m_rt = NULL;
+ list_for_each_entry_safe(m_rt, _m_rt,
+ &stream->master_list, stream_node) {
+
+ if (m_rt->bus != bus)
+ continue;
+
+ sdw_master_port_release(bus, m_rt);
+ sdw_release_master_stream(m_rt, stream);
+ }
+
+ if (list_empty(&stream->master_list))
+ stream->state = SDW_STREAM_RELEASED;
When a master is removed, there is an explicit test to make sure the
stream state changes when there are no masters left in the list, but...
mutex_unlock(&bus->bus_lock);
@@ -1127,7 +1169,7 @@ int sdw_stream_add_master(struct sdw_bus
*bus,
stream->state = SDW_STREAM_CONFIGURED;
... it's not symmetrical for the add_master case. The stream state
changes on the first added master. In addition the stream state
changes both when a slave is added and a master is added.
Is this intentional or not - and are there side effects resulting
from this inconsistency?
For remove_master, we already know the number of Masters in the stream
and hence we change the state to RELEASED only when there are no
Masters left in stream.
But, in the add_master case, we have no idea on how many master
instances are part of the stream and hence how many times add_master
would be called.
So, we change the stream state to CONFIGURED when the first Master is
added.
I can add a comment if that helps :)
I get the point, but you currently change the state for the first slave that's
added, so there is an inconsistency here (even before we add the multi-master
support).
When we add a slave, we check if there is an existing m_rt for that bus instance
and if It does not exist we create a m_rt for that master instance, add the slave
runtime and change the state to CONFIGURED. So technically we still change
the state after adding the first m_rt.
If you made no assumption on the order in which slaves and masters are
added then you need this assignment to CONFIGURED twice. But if you know
the slaves are added first then the second assignment is irrelevant.
It's hard to memorize really since there are parts where you assume
things are triggered by external events and others where there is no
assumption on API use...
If I wanted to split hair I'd also note it's almost like the state is CONFIGURING
rather than CONFIGURED if you don't really control when all configurations are
complete at the bus level and depend on external transitions (e.g. DAPM/ALSA
initiated) to go in PREPARED mode.
Yes, it is added intentionally (or rather because we could not think
of any other suitable way) and we dont see any side effects. Anything
that you could think of?
We should check what happens if the stream is removed before being enabled,
or all cases of testing stream->state.
While releasing the stream we unconditionally clean up things without checking
stream state. So, we should be fine that way. But, I can check these :)
A quick check for stream->state gives me this:
stream->state = SDW_STREAM_CONFIGURED;
>>> so here it's a success case but we fallback to an error case...
stream_error:
sdw_release_master_stream(m_rt, stream);
error:
mutex_unlock(&bus->bus_lock);
return ret;
You are probably missing a
stream->state = SDW_STREAM_CONFIGURED;
goto error; //<<< Add this
as done for the slave?
Wondering how this ever worked, you may want to triple-check the regular
stream management before adding the multi-master stuff?
--Shreyas
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