Messages in this thread |  | | | Date | Thu, 30 Sep 2010 18:14:35 -0400 (EDT) | | From | Len Brown <> | | Subject | Re: [PATCH] intel_idle: PCI quirk to prevent Lenovo Ideapad s10-3 boot hang |
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> > When the Lenovo Ideapad S10-3 is booted with HT enabled, > > it hits a boot hang in the intel_idle driver. > > > > This occurs when entering ATM-C4 for the first time, > > unless BM_STS is first cleared. > > > > acpi_idle doesn't see this because it first checks > > and clears BM_STS, but it would hit the same hang > > if that check were disabled. > > If there's hardware that expects BM_STS to be cleared, and if we've > previously always cleared BM_STS, shouldn't intel_idle be doing the same > thing?
No, we don't always clear BM_STS with acpi_idle -- we check (and clear) that bit only if the acpi tables tell us to do so.
BM_STS is a status bit, not a control bit. It is a surprise that the NM10 chip-set requires that it be cleared -- apparently once at boot time.
No, I don't want intel_idle to know about this chip-set quirk, and I don't want to add an IO access to the idle hot path if we can possibly avoid it.
thanks, Len Brown, Intel Open Source Technology Center
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