diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2008-08-16 17:14:07 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-08-16 17:14:07 -0700 |
commit | 0473b7992943ee7b182aa4afeb602ba5d37d36e0 (patch) | |
tree | 87487edbdd9c7ecc6c4f06ddf50cede10523e65e /arch/x86/kernel/hpet.c | |
parent | Move sysctl check into debugging section and don't make it default y (diff) | |
parent | x86: add MAP_STACK mmap flag (diff) | |
download | linux-dev-0473b7992943ee7b182aa4afeb602ba5d37d36e0.tar.xz linux-dev-0473b7992943ee7b182aa4afeb602ba5d37d36e0.zip |
Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (32 commits)
x86: add MAP_STACK mmap flag
x86: fix section mismatch warning - spp_getpage()
x86: change init_gdt to update the gdt via write_gdt, rather than a direct write.
x86-64: fix overlap of modules and fixmap areas
x86, geode-mfgpt: check IRQ before using MFGPT as clocksource
x86, acpi: cleanup, temp_stack is used only when CONFIG_SMP is set
x86: fix spin_is_contended()
x86, nmi: clean UP NMI watchdog failure message
x86, NMI: fix watchdog failure message
x86: fix /proc/meminfo DirectMap
x86: fix readb() et al compile error with gcc-3.2.3
arch/x86/Kconfig: clean up, experimental adjustement
x86: invalidate caches before going into suspend
x86, perfctr: don't use CCCR_OVF_PMI1 on Pentium 4Ds
x86, AMD IOMMU: initialize dma_ops after sysfs registration
x86m AMD IOMMU: cleanup: replace LOW_U32 macro with generic lower_32_bits
x86, AMD IOMMU: initialize device table properly
x86, AMD IOMMU: use status bit instead of memory write-back for completion wait
x86: silence mmconfig printk
x86, msr: fix NULL pointer deref due to msr_open on nonexistent CPUs
...
Diffstat (limited to 'arch/x86/kernel/hpet.c')
-rw-r--r-- | arch/x86/kernel/hpet.c | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c index ad2b15a1334d..59fd3b6b1303 100644 --- a/arch/x86/kernel/hpet.c +++ b/arch/x86/kernel/hpet.c @@ -359,6 +359,7 @@ static int hpet_clocksource_register(void) int __init hpet_enable(void) { unsigned long id; + int i; if (!is_hpet_capable()) return 0; @@ -369,6 +370,29 @@ int __init hpet_enable(void) * Read the period and check for a sane value: */ hpet_period = hpet_readl(HPET_PERIOD); + + /* + * AMD SB700 based systems with spread spectrum enabled use a + * SMM based HPET emulation to provide proper frequency + * setting. The SMM code is initialized with the first HPET + * register access and takes some time to complete. During + * this time the config register reads 0xffffffff. We check + * for max. 1000 loops whether the config register reads a non + * 0xffffffff value to make sure that HPET is up and running + * before we go further. A counting loop is safe, as the HPET + * access takes thousands of CPU cycles. On non SB700 based + * machines this check is only done once and has no side + * effects. + */ + for (i = 0; hpet_readl(HPET_CFG) == 0xFFFFFFFF; i++) { + if (i == 1000) { + printk(KERN_WARNING + "HPET config register value = 0xFFFFFFFF. " + "Disabling HPET\n"); + goto out_nohpet; + } + } + if (hpet_period < HPET_MIN_PERIOD || hpet_period > HPET_MAX_PERIOD) goto out_nohpet; |