On Wed, May 20, 2020 at 8:40 AM Emmanuel Grumbach <egrumbach@xxxxxxxxx> wrote: > Since I have been involved quite a bit in the firmware debugging > features in iwlwifi, I think I can give a few insights here. > > But before this, we need to understand that there are several sources of issues: > 1) the firmware may crash but the bus is still alive, you can still > use the bus to get the crash data > 2) the bus is dead, when that happens, the firmware might even be in a > good condition, but since the bus is dead, you stop getting any > information about the firmware, and then, at some point, you get to > the conclusion that the firmware is dead. You can't get the crash data > that resides on the other side of the bus (you may have gathered data > in the DRAM directly, but that's a different thing), and you don't > have much recovery to do besides re-starting the PCI enumeration. > > At Intel, we have seen both unfortunately. The bus issues are the ones > that are trickier obviously. Trickier to detect (because you just get > garbage from any request you issue on the bus), and trickier to > handle. One can argue that the kernel should *not* handle those and > let this in userspace hands. I guess it all depends on what component > you ship to your customer and what you customer asks from you :). Or the two best approaches: 1) get rid of firmware completely; 2) make it OSS (like SOF). I think any of these is a right thing to do in long-term perspective. How many firmwares average computer has? 50? 100? Any of them is a burden and PITA. -- With Best Regards, Andy Shevchenko
