Messages in this thread | | | Date | Wed, 12 Dec 2007 16:12:45 +0000 | From | Alan Cox <> | Subject | Re: RFC: outb 0x80 in inb_p, outb_p harmful on some modern AMD64 with MCP51 laptops |
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There is another reason we can't just do a dumb changeover - two actually
#1: Some drivers are using inb_p/outb_p in PCI cases which are going to cause PCI posting changes. Most are probably just wrong in the first place but they need hand checking
#2: We've got SMP cases that only 'work' because the odds of splitting the outb and the following port 0x80 cycle, which locks the bus, are tiny.
That is we've got
CPU1 CPU2 main path irq path outb outb
inb 0x80 inb 0x80
races in one or two spots.
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