On Thu, Feb 18, 2021 at 12:43:30PM -0500, Jon Masters wrote: > Hi Bjorn, all, > > On Thu, Jan 28, 2021 at 6:31 PM Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > > On Tue, Jan 26, 2021 at 10:46:04AM -0600, Jeremy Linton wrote: > > > > > Does that mean its open season for ECAM quirks, and we can expect > > them to start being merged now? > > "Open season" makes me cringe because it suggests we have a license to > use quirks indiscriminately forever, and I hope that's not the case. > > Lorenzo is closer to this issue than I am and has much better insight > into the mess this could turn into. From my point of view, it's > shocking how much of a hassle this is compared to x86. There just > aren't ECAM quirks, in-kernel clock management, or any of that crap. > I don't know how they do it on x86 and I don't have to care. Whatever > they need to do, they apparently do in AML. Eventually ARM64 has to > get there as well if vendors want distro support. > > I don't want to be in the position of enforcing a draconian "no more > quirks ever" policy. The intent -- to encourage/force vendors to > develop spec-compliant machines -- is good, but it seems like the > reward of having compliant machines "just work" vs the penalty of > having to write quirks and shepherd them upstream and into distros > will probably be more effective and not much slower. > > > The problem is that the third party IP vendors (still) make too much junk. For > years, there wasn't a compliance program (e.g. SystemReady with some of the > meat behind PCI-SIG compliance) and even when there was the third party IP > vendors building "root ports" (not even RCs) would make some junk with a hacked > up Linux kernel booting on a model and demo that as "PCI". There wasn't the > kind of adult supervision that was required. It is (slowly) happening now, but > it's years and years late. It's just embarrassing to see the lack of ECAM that > works. In many cases, it's because the IP being used was baked years ago or > made for some "non server" (as if there is such a thing) use case, etc. But in > others, there was a chance to do it right, and it still happens. Some of us > have lost what hair we had over the years getting third party IP vendors to > wake up and start caring about this. > > So there's no excuse. None at all. However, this is where we are. And it /is/ > improving. But it's still too slow, and we have platforms still coming to > market that need to boot and run. Based on this, and the need to have something > more flexible than just solving for ECAM deficiencies (which are really just a > symptom), I can see the allure of an SMC. I don't like it, but if that's where > folks want to go, and if we can find a way to constrain the enthusiasm for it, > then perhaps it is a path forward. But if we are to go down that path it needs > to come with a giant warning from the kernel that a system was booted at is > relying on that. Something that will cause an OS certification program to fail > without a waiver, or will cause customers to phone up for support wondering why > the hw is broken. It *must* not be a silent thing. It needs to be "this > hardware is broken and non-standard, get the next version fixed". It is a stance I agree with in many respects, it should be shared (it was in HTML format - the lists unfortunately dropped the message) so I am replying to it to make it public. Thanks, Lorenzo
