[PATCH] i386: Handle non existing APICs without panicing

[description from AK]

This fixes booting in APIC mode on some ACER laptops. x86-64
did a similar change some time ago.

See http://bugzilla.kernel.org/show_bug.cgi?id=4700 for details

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/arch/i386/kernel/io_apic.c b/arch/i386/kernel/io_apic.c
index f2dd218..235822b 100644 (file)
--- a/arch/i386/kernel/io_apic.c
+++ b/arch/i386/kernel/io_apic.c
@@ -2566,8 +2566,10 @@ int __init io_apic_get_unique_id (int ioapic, int apic_id)
                spin_unlock_irqrestore(&ioapic_lock, flags);
 
                /* Sanity check */
-               if (reg_00.bits.ID != apic_id)
-                       panic("IOAPIC[%d]: Unable change apic_id!\n", ioapic);
+               if (reg_00.bits.ID != apic_id) {
+                       printk("IOAPIC[%d]: Unable to change apic_id!\n", ioapic);
+                       return -1;
+               }
        }
 
        apic_printk(APIC_VERBOSE, KERN_INFO

diff --git a/arch/i386/kernel/mpparse.c b/arch/i386/kernel/mpparse.c
index e7609ab..e6e2f43 100644 (file)
--- a/arch/i386/kernel/mpparse.c
+++ b/arch/i386/kernel/mpparse.c
@@ -915,6 +915,7 @@ void __init mp_register_ioapic (
        u32                     gsi_base)
 {
        int                     idx = 0;
+       int                     tmpid;
 
        if (nr_ioapics >= MAX_IO_APICS) {
                printk(KERN_ERR "ERROR: Max # of I/O APICs (%d) exceeded "
@@ -935,9 +936,14 @@ void __init mp_register_ioapic (
 
        set_fixmap_nocache(FIX_IO_APIC_BASE_0 + idx, address);
        if ((boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) && (boot_cpu_data.x86 < 15))
-               mp_ioapics[idx].mpc_apicid = io_apic_get_unique_id(idx, id);
+               tmpid = io_apic_get_unique_id(idx, id);
        else
-               mp_ioapics[idx].mpc_apicid = id;
+               tmpid = id;
+       if (tmpid == -1) {
+               nr_ioapics--;
+               return;
+       }
+       mp_ioapics[idx].mpc_apicid = tmpid;
        mp_ioapics[idx].mpc_apicver = io_apic_get_version(idx);
        
        /*