Messages in this thread | | | Date | Thu, 2 Aug 2007 12:56:31 +0100 | From | Matthew Garrett <> | Subject | Re: 2.6.22 regression: thermal trip points |
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On Thu, Aug 02, 2007 at 01:45:00PM +0200, Thomas Renninger wrote: > On Thu, 2007-08-02 at 12:13 +0100, Matthew Garrett wrote: > > I strongly suspect that the vast majority[1] of hardware that "needs" > > the trip points changing works perfectly well under Windows, so it's > > likely to be papering over bugs in the kernel. It'd be nice if we fixed > > those rather than encouraging people to poke stuff into /proc, > Some arguments against that: > - You cannot tell a customer: Wait for the kernel in half a year. > This is the time it at least needs until a laptop got sold, the > problem is found, a patch is written and checked in and finally > hits the distribution.
We have to do so frequently. New hardware often exposes bugs in the kernel.
> - You can also not backport fixes as ACPI patches mostly have the > potential to break other machines/BIOSes > - There also exist the policy to not fix up/workaround totally broken > AML BIOS implementations
The policy has been to attempt to be bug-compatible with Windows whenever possible for some time now.
> - We do not need to and never will be able to copy or do the same > Windows is doing
Given that many vendors still only test against Windows, that's exactly what we need to do.
> > especially when doing so is guaranteed to break in really confusing ways > > with a lot of hardware. The firmware can reset the trip points at > > essentially arbitrary times and is well within its rights to expect the > > OS to actually pay attention to them. > What the hell is so wrong with: > > Let the user override the trip points. If he does so, ignore > thermal trip point updates from BIOS. Don't care for hysteresis > BIOS implementations (these are the BIOS trip point updates).
No, that's not the only reason for notifications. Alteration in hardware state may also force a recalculation of trip point (adding a battery to a bay rather than a DVD drive may require the platform to be kept at a lower temperature)
> If user changes them, it's his fault, he doesn't need to... > Make sure that trip points can only be lowered, compared to the > initially fetched one from BIOS.
Surely people want this functionality so that they can raise trip points?
-- Matthew Garrett | mjg59@srcf.ucam.org - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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