On Tue, 2018-07-03 at 17:17 +0200, Ard Biesheuvel wrote: > On 3 July 2018 at 10:44, Ian Campbell <ijc@xxxxxxxxxx> wrote: > > On Thu, 2018-06-28 at 12:25 +0200, Ard Biesheuvel wrote: > > > I understand the desire to keep running these M400s as long as they > > > have some life left in them, but the reality is that they are end of > > > life already, and not many were manufactured to begin with. > > > > Linux has a long history of supporting such devices so long as there is > > someone around willing to keep them running (witness for example how > > long x86/voyager lived with just 1 in existence in a motivated > > developer's basement, probably some number of entire architectures and > > I bet a not insubstantial chunk of the platform support in arch/arm). > > > > I wonder how many such quirks fall into the 'user cannot be bothered > to add a kernel command line option' category. I don't know the overall picture, but the very first one I happened to look at in arch/x86/kernel/acpi/boot.c (picked by grepping for quirk and looking for acpi) just now was half a dozen quirks setting acpi_skip_timer_override which is also settable on the command line. There's also a bunch in there which just disable ACPI completely which is also possible on the command line. My gut feeling is that these are the rule not the exception. > > So, I think DMI quirks are probably, in reality, inevitable unless > > you > > think firmware authors are going to be infaliable or the > > testing/certification suites never has any gaps in it. > > > > Oh, obviously. But this is exactly my point about flood gates: we know > we need implement support for them, but that fact alone does not > justify adding quirks for dead platforms for issues that can be > trivially worked around. Is m400 really dead? There certainly seem to be people around who care about keeping it running and have access to them. > On a related note: what we *could* do to accommodate platforms such as > m400 that are affected by quirks that can be worked around by a > command line parameter: we could teach the stub to look at the > contents of the 'LinuxExtraArgs' EFI environment variable and append > it to the kernel command line. This is trivial to implement, given > that we already manipulate and parse the command line in the stub, and > would allow for a 'fix and forget' tweak to be applied to such > platforms., without having to accumulate quirks for broken platforms > that are difficult to remove later. Ideally the quirk would be a single entry in a table, which is unobtrusive enough not to worry about removing. Ian. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
