New Linux Patch Series Proposes Gating "Legacy PCI" Support

[phoronix]

Phoronix: New Linux Patch Series Proposes Gating "Legacy PCI" Support

A patch series sent out by IBM would introduce a new "LEGACY_PCI" Kconfig option for gating legacy PCI device support, including PCI devices attached to PCI-to-PCIe bridges and PCIe devices using legacy I/O spaces...

https://www.phoronix.com/scan.php?page=news_item&px=Linux-Gating-Legacy-PCI

[coder]

For the time being, it should either default to "on" or at least I hope the next round of LTS kernel builds keep it on!

I still have a few legacy PCI cards I might potentially use, at some point. And some industrial, long-life Skylake (and maybe newer) motherboards still have PCI slots.

[mr_marmalade]

I still use a Terratec DVB-T PCI card & it works perfectly well; hopefully it won't just stop working because someone decides to disable its hardware support to knock 0.1seconds off of kernel compile times. I also use a sound card, hopefully it isn't a PCI device using a PCIe bridge.

[schmidtbag]

I think it's a little too soon to remove PCI. As coder pointed out, there are still pretty modern platforms that still support it.

Features should only be removed from the kernel if they're outdated to the point where they serve no practical modern use, if it can't be properly maintained (in a way that hold back progress), or where less than 0.1% of Linux users use it.

[numacross]

This shouldn't default to N for at least 10 more years, or even longer.

Dell's current (10,11-th gen Intel CPUs) OptiPlex 7090 is still shipping with PCI. Despite having 4 M.2 slots and being a 12V-only motherboard (sadly a proprietary variant)

[direc85]

The point is IBM being able to cut out dead code for their own purposes, which in isolation is good. It's a switch after all, and I bet it will be on by default - I don't see who in their right minds would disable legacy PCI for desktops! Many mainboards still have an ISA bus for temp sensors, for example. Legacy doesn't mean deprecated. In my mind, it means stable/finished (and only maybe possibly deprecated )

[dlq84]

It's not getting removed, relax people...

[Quackdoc]

I like the idea, but it will be super annoying if this becomes on by default.

[direc85]

Even if it became a default, Ubuntu, Fedora, Manjaro et. al. will flip it on for quite a while

[F.Ultra]

For the time being, it should either default to "on" or at least I hope the next round of LTS kernel builds keep it on!

I still have a few legacy PCI cards I might potentially use, at some point. And some industrial, long-life Skylake (and maybe newer) motherboards still have PCI slots.

It's only implemented to remove the code for s390 so it will default to Yes for all other arcs for a long time still.