On Wed, 28 May 2014, Sebastian Andrzej Siewior wrote: > On 05/27/2014 09:58 PM, Thomas Gleixner wrote: > > ce4100 is an oddball though. The ioapic is registered way before the > > interrupt subsystem is initialized and I have a hard time to > > understand that comment: > > > > /* We can't set this earlier, because we need to calibrate the timer */ > > legacy_pic = &null_legacy_pic; > > > > The timer calibration happens after the interrupts are set up. I > > assume it's check_timer() which wants that, but we know exactly how > > the ce4100 works, so we might be able to avoid that whole "testing" > > stuff. Sebastian, any input on this? > > According to my memory there was some PIC init we need but I don't > recall the details. However, booting the system with "legacy_pic = > &null_legacy_pic;" in x86_ce4100_early_setup() gives me this: > > [ 0.001000] Enabling APIC mode: Flat. Using 2 I/O APICs > [ 0.001000] leaving PIC mode, enabling APIC mode. > [ 0.001000] enabled ExtINT on CPU#0 > [ 0.001000] ENABLING IO-APIC IRQs > [ 0.001000] Setting 1 in the phys_id_present_map > [ 0.001000] ...changing IO-APIC physical APIC ID to 1 ... ok. > [ 0.001000] Setting 2 in the phys_id_present_map > [ 0.001000] ...changing IO-APIC physical APIC ID to 2 ... ok. > [ 0.001000] smpboot: CPU0: Intel(R) Atom(TM) CPU CE4150 @ 1.20GHz > (fam: 06, model: 1c, stepping: 0a) > [ 0.001000] Using local APIC timer interrupts. > [ 0.001000] calibrating APIC timer ... > > and we stand still. With the assignment as it is now: > > [ 0.001000] Enabling APIC mode: Flat. Using 2 I/O APICs > [ 0.001000] leaving PIC mode, enabling APIC mode. > [ 0.001000] enabled ExtINT on CPU#0 > [ 0.002312] ENABLING IO-APIC IRQs > [ 0.003009] Setting 1 in the phys_id_present_map > [ 0.004007] ...changing IO-APIC physical APIC ID to 1 ... ok. > [ 0.005533] Setting 2 in the phys_id_present_map > [ 0.006006] ...changing IO-APIC physical APIC ID to 2 ... ok. > [ 0.008373] ..TIMER: vector=0x30 apic1=-1 pin1=-1 apic2=-1 pin2=-1 > [ 0.009000] ...trying to set up timer as Virtual Wire IRQ... > [ 0.019490] ..... works. Right, so it needs the setup of irq 0 and that only happens when the legacy_pic->nr_legacy_irqs > 0. Do you remember, why we switch to the null_pic later on? Thanks, tglx -- 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
