Subject: [PATCH V6 0/6] iommu/msm: Add DT adaptation and generic bindings support

From: [email-masked] (Sricharan)
Date: Fri, 12 Aug 2016 12:30:03 +0530

Hi Rob,

>> btw, the current state, at least on linaro integration branch, fault
>> handling doesn't work so well (ie. device never gets resumed).. which
>> is a bit unfortunate for a gpu (and results in a *lot* of rebooting on
>> my part when debugging userspace).  I haven't had time yet to compare
>> to the ancient downstream driver, but not sure if you have any ideas?
>>
>> I guess probably disabling stall on fault would help.  But I'm not
>> even getting the "Fault occurred in context.." prints.  Seeing the
>> fault iova is pretty useful since that plus gpu cmdstream trace helps
>> me figure out which texture/etc is being accessed out of bounds.
>
>fyi, it looks like it is not getting any fault irq..  it's *possible*
>that I screwed up the irq #'s when translating from downstream, so you
>might want to double check that.  I thought I had it right, I assume I
>would have noticed during piglit runs if fault recovery wasn't working
>(since the result is that *everything* after the faulting test would
>have failed since gpu is wedged with no access to memory), but it was
>long enough ago that I can't claim that definitively.
>
>If you need an easy way to trigger a gpu fault, msmtest is a good way,
>change this line:
>
>  https://github.com/freedreno/msmtest/blob/master/msmtest.c#L247
>
>from OUT_RELOC() to OUT_RING(ring, 0x00000000) will trigger a fault.
>
   So for the irq to be triggered, 'non-secure' irq line has to be
  populated in DT. There is a 'secure'and 'non-secure' irq lines for these iommus
  and  non-secure irq number is secure + 1. I tested this by having a 'return 0'
 from the msm_iommu_map (no mapping), and the faults were getting triggered.

  Can you share me your dts data ?

Regards,
 Sricharan