Re: possible deprecation and removal of some old QEMU Arm machine types (pxa2xx, omap, sa1110)

[Arnd Bergmann]

On Wed, Feb 14, 2024, at 02:27, Aaro Koskinen wrote:
> On Tue, Feb 13, 2024 at 09:11:38PM +0100, Arnd Bergmann wrote:
>
> I'm one of the OMAP1 Linux kernel maintainers, and I have Palm TE which
> I have been using for testing and development (and reporting bugs,
> regressions) along with those other boards you mentioned.
>
> Since I have the real Palm HW, I haven't used QEMU for that particular
> board. But however I use QEMU SX1 support frequently as it's quickest way
> to check if OMAP1 is bootable, and if the basic peripherals are working.
> SX1 is close to Palm/AMS-Delta, and also it's ARMv4T which is rare these
> days. I think it's useful to keep it in QEMU as long there are hardware
> that people use.
>
> So my wish is to keep at least SX1 support in QEMU as long as ARMv4T
> supported in the Linux kernel.

Makes sense. We have a couple of other ARMv4T systems in the kernel
that are still being tested (ep93xx, at91rm9200, clps71xx, imx1,
nspire, integrator/ap), but none of the others have any qemu
support apparently unless you count "-Mintegratorpb -cpu arm925".
All of these are are using DT or getting there (ep93xx), so we'll
probably keep them around for a while.

Similarly, we support a couple of ARMv4 (non-T) targets in the
kernel (footbridge, sa1100, rpc, moxart, gemini), but the only
one with qemu support here is sa1100/collie.

>> >> > > OMAP2 machines:
>> >> > >
>> >> > > n800                 Nokia N800 tablet aka. RX-34 (OMAP2420)
>> >> > > n810                 Nokia N810 tablet aka. RX-44 (OMAP2420)
>> >> > >
>> >> > I never managed to get those to boot the Linux kernel.
>> 
>> I think Tony still tests these on both hardware and qemu.
>> The platform side here is much more modern than any of the
>> others above since it does use DT and it has enough RAM
>> to be somewhat usable.
>
> I have also these boards (real hardware) and test them frequently with
> mainline Linux. However, QEMU support I haven't used/needed. I recall it
> was a bit buggy, and some changes in mainline made the kernel unbootable.
> Unless Tony needs the support, I guess they are good to go.

Thanks for confirming.

> (Arnd: RAM isn't everything. Some of the OMAP1 boards today are still
> more useful than N800/N810, even with modern bloaty Linux.)

Obviously RAM isn't everything, but the machines with just 32MB
or less do seem very small for real workloads, so I admit I
dismiss them easily. I am curious what you run on those, are
there any embedded distros that maintain good support for 32MB
systems on modern kernel/musl/Xorg/..., or are you using
omething older or highly customized?

     Arnd