Messages in this thread | | | From | (bill davidsen) | Subject | Re: Can we kill f inb_p, outb_p and other random I/O on port 0x80, in 2.6? | Date | 23 Sep 2003 18:41:28 GMT |
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In article <20030922215432.GE29869@mail.jlokier.co.uk>, Jamie Lokier <jamie@shareable.org> wrote: | linux@horizon.com writes: | > > So can we gradually kill inb_p, outb_p in 2.6? An the other | > > miscellaneous users of I/O port 0x80 for I/O delays? | > | > Actually, It's not easy. The issue got debated a lot a few years ago. | > A read is also acceptable, and allows a few more ports to be | > potentially used, but that corrupts %al and thus bloats the code. | | It bloats the code a lot less than udelay() calls or any other | solution which keeps the delay! | | In the worst case, the bloat from a read _should_ be two bytes: "push | %eax; inb $80,%al; pop %eax". Whereas a call to udelay is 5 bytes, | for a call instruction.
Isn't one of the benefits of a rethink not to use any i/o bus cycles?
-- bill davidsen <davidsen@tmr.com> CTO, TMR Associates, Inc Doing interesting things with little computers since 1979. - 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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