On Fri, 19 Dec 2008, Wu Fengguang wrote: > On Fri, Dec 19, 2008 at 10:38:18AM +0200, Len Brown wrote: > > > The issue on Fengguang's laptop is different with that on the box of > > > T61. On Fengguang's laptop after evaluating one ACPI object(GPE > > > _L18object), the irq is disabled mystically. After some investigations > > > we find that it is caused by SMI(The SMI will be triggered while > > > evaluating the ACPI object. And this issue is also related with Video). > > > > Interesting. > > I hadn't realized you root-caused that failure. > > This is good to know, but the fact that SMM can > > leave interrupts disabled is frightening. > > > If the BIOS SMM on that box disables interrupts when > > random AML is run, then it is going to run into > > all kinds of other problems in addition to this one... > > Exactly. This is another warning: > > [ 6559.754331] irq status before SMI: enable > [ 6559.757388] irq status after SMI: disable, value: 0xF3 > [ 6599.816127] Corrupted low memory at ffff88000000fe08 (fe08 phys) = 01007062 > [ 6599.816253] Corrupted low memory at ffff88000000fe10 (fe10 phys) = 7ba83066 > [ 6599.816376] Corrupted low memory at ffff88000000fe18 (fe18 phys) = 00010062 > [ 6599.816492] Corrupted low memory at ffff88000000fe20 (fe20 phys) = 01006062 I proposed a long term fix for this years ago. If it had been implemented, this insanity would not be possible. Every time a BIOS writer uses SMM, they should be rewarded by having a digit severed. This is a very simple proposal, very easy to understand. Further, with "10-strikes and you're out", it comprehends that there may be some BIOS writerse that take a while to catch on... However, when they run out of fingers I'd draw the line and insist that they find a new line of work. -Len -- 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
