Messages in this thread | | | Date | Wed, 1 Jun 2005 17:32:32 +0200 | From | Andrea Arcangeli <> | Subject | Re: RT patch acceptance |
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On Wed, Jun 01, 2005 at 05:15:23PM +0200, Esben Nielsen wrote: > redifiing cli()/sti() in Linux, which is what the patent covers.
I'm glad at least I understood something right about the patent contents.
These days cli/sti are more commonly called local_irq_disable/local_irq_enable.
So clearly renaming cli/sti to local_irq_disable/enable isn't going to invalidate the patent.
I don't know if spin_lock_irq can be considered a way to disable hard irqs or not, and if doing the _irq part in a "soft" mode that leaves hard-irq enabled can be considered "software emulation".
It'm not a laywer so I can't know that.
> Neither am I. But I know if I start to interpret patens that way I would > have to stop writing software right now as every line of code would be > covered by some patent if you start to look at it your way.
This is true. Well, the only thing I really known was the patent covered the redefinition of cli not to do an hard "cli" asm instruction, but to do it in software (i.e. emulated). nanokernel worked around that since it did it for ages before the patent was filed (so at the very least that would make the patent invalid, sure nanokernel non-GPL usage isn't infringing).
This one of preempt-rt looked to redefine a hard-disable-irq to a soft-disable-irq in the context of the OS, and in turn my mind immediatly went back to the patent.
BTW, I remind people to sign the petition (I already signed it some time ago):
http://petition.eurolinux.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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