Hi Felix, On Wed, 2023-05-03 at 11:08 -0400, Felix Kuehling wrote: > That's the worst-case scenario where you're debugging HW or FW > issues. > Those should be pretty rare post-bringup. But are there hangs caused > by > user mode driver or application bugs that are easier to debug and > probably don't even require a GPU reset? There are many GPU hangs that gamers experience while playing. We have dozens of open bug reports against RADV about GPU hangs on various GPU generations. These usually fall into two categories: 1. When the hang always happens at the same point in a game. These are painful to debug but manageable. 2. "Random" hangs that happen to users over the course of playing a game for several hours. It is absolute hell to try to even reproduce let alone diagnose these issues, and this is what we would like to improve. For these hard-to-diagnose problems, it is already a challenge to determine whether the problem is the kernel (eg. setting wrong voltages / frequencies) or userspace (eg. missing some synchronization), can be even a game bug that we need to work around. > For example most VM faults can > be handled without hanging the GPU. Similarly, a shader in an endless > loop should not require a full GPU reset. This is actually not the case, AFAIK André's test case was an app that had an infinite loop in a shader. > > It's more complicated for graphics because of the more complex > pipeline > and the lack of CWSR. But it should still be possible to do some > debugging without JTAG if the problem is in SW and not HW or FW. It's > probably worth improving that debugability without getting hung-up on > the worst case. I agree, and we welcome any constructive suggestion to improve the situation. It seems like our idea doesn't work if the kernel can't give us the information we need. How do we move forward? Best regards, Timur
