Hello everyone, I'm consistently getting a system crash followed by a ramdump on sa8540p-ride (sc8280xp) when icc_sync_state() goes all the way through (count == providers_count). Context: all PCIe buses are disabled due to [1]. Previously, due to some local kernel misconfiguration, icc_sync_state() never really did anything (because count was always less than providers_count). I was able to isolate the problem to the qns_pcie_gem_noc icc node. What happens is that both avg_bw and peak_bw for this node end up as 0 after aggregate_requests() gets called. The request list associated with the node is empty. For testing purposes, I modified icc_sync_state() to skip calling aggregate_requests() and subsequently p->set(n, n) for that particular node only. With that change in place, the system no longer crashes. Surprisingly, none of the icc nodes that link to qns_pcie_gem_noc (e.g. xm_pcie3_0, xm_pcie3_1, etc.) has any associated request and so they all have 0 bandwidth after aggregate_requests() gets called, but that doesn't seem to be a problem and the system is stable. This makes me think there is a missing link somewhere, and something doesn't claim any bandwidth on qns_pcie_gem_noc when it should. And it's probably none of the xm_pcie3_* nodes, since setting their bandwidth to 0 seems to be fine. For what is worth, when pcie2a is not disabled, xm_pcie3_2a ends up with avg_bw=0kBps and peak_bw=1970000kBps, which is also reflected in qns_pcie_gem_noc. Both of these nodes get a request from 1c20000.pcie: # cat /sys/kernel/debug/interconnect/interconnect_summary node tag avg peak -------------------------------------------------------------------- ... xm_pcie3_2a 0 1970000 1c20000.pcie 0 0 1970000 ... qns_pcie_gem_noc 0 1970000 1c20000.pcie 0 0 1970000 ... Any thoughts or suggestions would be highly appreciated. Thanks! Best regards, Radu Rendec [1] https://lore.kernel.org/linux-arm-msm/pmodcoakbs25z2a7mlo5gpuz63zluh35vbgb5itn6k5aqhjnny@jvphbpvahtse/
