On Fri, 31 Aug 2007 14:31:51 +0400
Konstantin Baydarov <kbaidarov at ru.mvista.com> wrote:
> On Thu, 30 Aug 2007 12:04:33 -0600
> ebiederm at xmission.com (Eric W. Biederman) wrote:
>
> > I was assuming that CLOCK_EVT_MODE_SHUTDOWN just mapped
> > to the shutdown method of the clock events or something else.
> > But it shutdown means something different in this context we
> > can certainly find a better place to hook into the device
> > tree and call shutdown methods. Especially if that will
> > make the code simpler.
>
> Agree. I've got rig from timekeeping. Now I'm using system device
> tree shutdown interface, as you suggested. I've added HPET system
> device class with shutdown method and HPET device to sysdev.
>
> > This is a design feature. machine_crash_shutdown is not really
> > supposed to disable any hardware. There is a very minimal set that
> > we haven't been able to figure out how to get the kernels
> > initialization routines to deal with properly. Which is a
> > temporary justification for not doing more now. If we can't find
> > anyway to make the initialization code more robust for the hpet we
> > can revisit this.
>
> So you suggest to check if HPET is present in HPET init code even if
> HPET disabled in boot kernel command line or APIC is disabled. And if
> HPET is present and kernel not going to use it - disable HPET
> interrupts?
>
> > Please remove the CONFIG_KEXEC. We need to do this on a reboot also
> > so we don't confuse the BIOS. BIOS's frequently but not always
> > can just reset the board to avoid complications like this, but if
> > we need a shutdown method we need a shutdown method. The kexec
> > case just exercises things more.
> Removed CONFIG_KEXEC.
>
> So here is new version of fix. Patch against 2.6.23-rc3.
> Eric, review please. Thanks.
>
> Signed-off-by: Konstantin Baydarov <kbaidarov at ru.mvista.com>
>
> arch/i386/kernel/hpet.c | 48
> ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48
> insertions(+)
>
> Index: linux-2.6.23-rc3/arch/i386/kernel/hpet.c
> ===================================================================
> --- linux-2.6.23-rc3.orig/arch/i386/kernel/hpet.c
> +++ linux-2.6.23-rc3/arch/i386/kernel/hpet.c
> @@ -144,11 +144,31 @@ static void hpet_enable_int(void)
> {
> unsigned long cfg = hpet_readl(HPET_CFG);
>
> + if (hpet_legacy_int_enabled)
> + return;
> +
> cfg |= HPET_CFG_LEGACY;
> hpet_writel(cfg, HPET_CFG);
> hpet_legacy_int_enabled = 1;
> }
>
> +static void hpet_disable_int(void)
> +{
> + unsigned long cfg;
> +
> + if (!hpet_legacy_int_enabled)
> + return;
> +
> + if (!is_hpet_capable())
> + return;
> +
> + cfg = hpet_readl(HPET_CFG);
> + cfg &= ~HPET_CFG_LEGACY;
> + hpet_writel(cfg, HPET_CFG);
> + hpet_legacy_int_enabled = 0;
> +
> +}
> +
> static void hpet_set_mode(enum clock_event_mode mode,
> struct clock_event_device *evt)
> {
> @@ -551,3 +571,31 @@ irqreturn_t hpet_rtc_interrupt(int irq,
> return IRQ_HANDLED;
> }
> #endif
> +
> +static int hpet_shutdown(struct sys_device *dev)
> +{
> + /* We need this to make PIT works in KEXECuted kernel */
> + hpet_disable_int();
> +
> + return 0;
> +}
> +
> +static struct sysdev_class hpet_sysdev_class = {
> + set_kset_name("hpet"),
> + .shutdown = hpet_shutdown,
> +};
> +
> +static struct sys_device device_hpet = {
> + .id = 0,
> + .cls = &hpet_sysdev_class,
> +};
> +
> +static int __init hpet_init_sysfs(void)
> +{
> + int error = sysdev_class_register(&hpet_sysdev_class);
> + if (!error)
> + error = sysdev_register(&device_hpet);
> + return error;
> +}
> +
> +device_initcall(hpet_init_sysfs);
> -
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Eric, can you tell me, when are you going to review last version of fix?
Thanks.
