On 19/02/2020 22:54, Olof Johansson wrote: Hi, > On Tue, Feb 18, 2020 at 10:14 AM Andre Przywara <andre.przywara@xxxxxxx> wrote: >> >> On Tue, 18 Feb 2020 11:13:10 -0600 >> Rob Herring <robh@xxxxxxxxxx> wrote: >> >> Hi, >> >>> Calxeda has been defunct for 6 years now. Use of Calxeda servers carried >>> on for some time afterwards primarily as distro builders for 32-bit ARM. >>> AFAIK, those systems have been retired in favor of 32-bit VMs on 64-bit >>> hosts. >>> >>> The other use of Calxeda Midway I'm aware of was testing 32-bit ARM KVM >>> support as there are few or no other systems with enough RAM and LPAE. Now >>> 32-bit KVM host support is getting removed[1]. >>> >>> While it's not much maintenance to support, I don't care to convert the >>> Calxeda DT bindings to schema nor fix any resulting errors in the dts files >>> (which already don't exactly match what's shipping in firmware). >> >> While every kernel maintainer seems always happy to take patches with a negative diffstat, I wonder if this is really justification enough to remove a perfectly working platform. I don't really know about any active users, but experience tells that some platforms really are used for quite a long time, even if they are somewhat obscure. N900 or Netwinder, anyone? > > One of the only ways we know to confirm whether there are active users > or not, is to propose removing a platform. > > The good news is that if/when you do, and someone cares enough about > it to want to keep it alive, they should also have access to hardware > and can help out in maintaining it and keeping it in a working state. > > For some hardware platforms, at some point in time it no longer makes > sense to keep the latest kernel available on them, especially if > maintainers and others no longer have easy access to hardware and > resources/time to keep it functional. > > It's really more about "If you care about this enough to keep it > going, please speak up and help out". I understand that, hence this email ;-) I just wanted to avoid the impression that, by looking at the replies on the list, *everybody* seems to be happy with the removal and it just goes ahead. I have no idea how many actual *users* read this list and this email. >> So to not give the impression that actually *everyone* (from that small subset of people actively reading the kernel list) is happy with that, I think that having support for at least Midway would be useful. On the one hand it's a decent LPAE platform (with memory actually exceeding 4GB), and on the other hand it's something with capable I/O (SATA) and networking, so one can actually stress test the system. Which is the reason I was using that for KVM testing, but even with that probably going away now there remain still some use cases, and be it for general ARM(32) testing. > > How many bugs have you found on this platform that you would not have > on a more popular one? And, how many of those bugs only affected this > platform, i.e. just adding onto the support burden without positive > impact to the broader community? I have found and helped fixing (or fixed myself) multiple bugs on the Midway in the past. The mixture of decent I/O and 8GB of DRAM seemed to be unique enough to spot bugs that didn't easily show on other systems. Most were on KVM, but some were generic, and I remember at least one LPAE related. And some bugs only showed under stress, because you can actually run something useful on that machine before it goes on its knees. >> I don't particularly care about the more optional parts like EDAC, cpuidle, or cpufreq, but I wonder if keeping in at least the rather small SATA and XGMAC drivers and basic platform support is feasible. > > At what point are you better off just running under QEMU/virtualization? For many things we are looking at that's not really an option. If it would be very involved or painful to keep the support alive (as in the KVM/arm32 case), I would see your point, but just some isolated drivers (really a few and mostly quite small) don't justify a removal, IMHO. I think we have far worse and older code in the kernel to worry about. >> If YAML DT bindings are used as an excuse, I am more than happy to convert those over. >> >> And if anyone has any particular gripes with some code, maybe there is a way to fix that instead of removing it? I was always wondering if we could get rid of the mach-highbank directory, for instance. I think most of it is Highbank (Cortex-A9) related. > > Again, how do you fix it if nobody has signed up for maintaining and > keeping it working? Doing blind changes that might or might not work > is not a way to keep a platform supported. > > Just because code is removed, it doesn't mean it can't be reintroduced > when someone comes along and wants to do that. Look at some of the > recent additions of old OLPC hardware support, for example. But > there's a difference between this and keeping the code around hoping > that someone will care about it. It's not lost, and it's easy to bring > back. OK, maybe I should have been more explicit: If Rob does not want to maintain it anymore, I am happy to throw my hat in the ring. I have a working Midway system under my desk, with at least four working nodes, two of them have an SSD connected and are running some off-the-shelf Ubuntu 18.04 or Debian userland. I mostly run mainline kernels, but try the distro kernels as well from time to time. Routinely I test at least every -rc1 for regressions. I also have updates to the A-15 firmware parts (U-Boot and PSCI runtime, including PSCI 1.0 support and a Spectre V2 workaround), and have a working setup to either chainload or actually update the firmware on the flash. Happy to share that if someone is interested. For U-Boot I wanted to send updates anyway. I also have an old Highbank system lying around, but haven't turned that on in years. So would just a patch to MAINTAINERS be a solution? Cheers, Andre
