On 10/2/24 10:50, Tomi Valkeinen wrote: > Hi, > > On 01/10/2024 21:31, Sean Anderson wrote: >> On 8/9/24 15:35, Sean Anderson wrote: >>> This series cleans up the zyqnmp_dp IRQ and locking situation. Once >>> that's done, it adds debugfs support. The intent is to enable compliance >>> testing or to help debug signal-integrity issues. > > I think the patches 1-7 look fine, and I think I can pick those already to drm-misc if you're ok with that. > > I'm a bit unsure about patch 8, probably mainly because I don't have experience with the compliance testing. > > How have you tested this? With some DP analyzer/tester, I presume? For my test setup I used an oscilloscope hooked up to the displayport output using a fixture that broke the signals out to SMA. Since the oscilloscope cannot emulate a sink, I first had the output connected to a monitor. Then I disabled HPD and reconnected the output to my fixture. This process is described in more detail in the documentation. > I think none of this (patch 8) is needed by almost anybody. Well, I found it very useful for debugging a signal integrity issue I was having. Once I could have a look at the signals it was very clear what the problem was. > Even among zynqmp_dp developers I assume it's very rare to have the > hardware for this. I wonder if it would make sense to have the debugfs > and related code behind a compile option (which would be nice as the > code wouldn't even compiled in), or maybe a module parameter (which > would be nice as then "anyone" can easily enable it for compliance > testing). What do you think? Other drivers with these features just enabled it unconditionally, so I didn't bother with any special config. > I also somehow recall that there was some discussion earlier about > how/if other drivers support compliance testing. But I can't find the > discussion. Do you remember if there was such discussion, and what was > the conclusion? With a quick look, everything in the debugfs looks > generic, not xilinx specific. The last it got discussed was back in [1], but I never got any further response. I agree that some of this is generic, and could probably be reworked into some internal helpers. But I don't have the bandwidth at the moment to do that work. --Sean [1] http://lore.kernel.org/dri-devel/cda22b0c-8d7c-4ce2-9a7c-3b5ab540fa1f@xxxxxxxxx
