Hi Mike,
On 2020-04-29 22:28, Mike Leach wrote:
Hi,
[...]
>> > You need to find what is resetting the IDFILTERs to 0 for replicator1.
>> >
>>
>> That is right.
>>
>
> By default all replicators have the IDFILTER registers set to 0 out of
> hardware reset. This ensures that programmable replicators behave in
> the same way as non-programmable replicators out of reset.
>
> The dynamic_replicator_reset() is of course a driver state reset -
> which filters out all trace on the output ports. The trace is then
> enabled when we set the trace path from source to sink.
>
Thanks for these explanations.
> It seems to me that you have 2 problems that need solving here:
>
> 1) Why does the reset_replicator() called from probe() _not_ work
> correctly on replicator 1? It seems to work later if you introduce a
> reset after more of the system has powered and booted. This is
> startiing to look a little like a PM / clocking issue.
reset_replicator() does work in probe correctly for both replicators,
below logs is collected before and after reset in probe. It is later
that it's set back to 0x0 and hence the suggestion to look at firmware
using this replicator1.
OK - sorry I read your statement saying that replicator1 was 0 after
the reset in probe(), rather than look at the logs.
From the logs it is working at the time probe() occurs, but by the
time we come to enable the replicator later, something has reset these
registers / hardware outside the control of the replicator driver.
Yes, I will try to get some more information from the firmware side if
there is anything messing up.
[ 8.477669] func replicator_probe before reset replicator
replicator1
REPLICATOR_IDFILTER0=0x0 REPLICATOR_IDFILTER1=0x0
[ 8.489470] func replicator_probe after reset replicator
replicator1
REPLICATOR_IDFILTER0=0xff REPLICATOR_IDFILTER1=0xff
>
> This failure is causing the state when we are trying to set an output
> port that both branches of this replicator are enabled for output.
> In effect for this replicator, setting the output port has no effect
> as it is already enabled.
>
> 2) Why does having both ports of this repilicator enabled cause a hard
> lockup? This is a separate hardware / system issue.
>
> The worst that should happen if both branches of a replicator are
> enabled is that you get undesirable back pressure. (e.g. there is a
> system we have seen - I think it is Juno - where there is a static
> replicator feeding the TPIU and ETR - we need to disable the TPIU to
> prevent undesired back pressure).
>
Ok so hardlockup is not expected because of this backpressure.
Hardlockup is not expected, but this is not related to any possible
backpressure.
Ordinarily having both legs of a replicator enabled should not cause
system failure.
Ok got it, thanks.
Thanks,
Sai
--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a
member
of Code Aurora Forum, hosted by The Linux Foundation
