Re: [PATCH] Blacklist Dell Optiplex 320 from using the HPET

Andrew Morton
2007-05-04T21:44:24Z

On Fri, 04 May 2007 14:29:04 -0700
john stultz <johnstul@us.ibm.com> wrote:

> One of the 2.6.21 regressions was Guilherme's problem seeing his box
> lock up when the system detected an unstable TSC and dropped back to
> using the HPET.
>
> In digging deeper, we found the HPET is not actually incrementing on
> this system. And in fact, the reason why this issue just cropped up was
> because of Thomas's clocksource watchdog code was comparing the TSC to
> the HPET (which wasn't moving) and thought the TSC was broken.
>
> Anyway, Guliherme checked for a BIOS update and did not find one, so
> I've added a DMI blacklist against his system so the HPET is not used.
>
> Many thanks to Guilherme for the slow and laborious testing that finally
> narrowed down this issue.
>

OK, I tagged that for -stable too.

>
> diff --git a/arch/i386/kernel/hpet.c b/arch/i386/kernel/hpet.c
> index 17d7345..1ae27f3 100644
> --- a/arch/i386/kernel/hpet.c
> +++ b/arch/i386/kernel/hpet.c
> @@ -5,6 +5,7 @@
> #include <linux/init.h>
> #include <linux/sysdev.h>
> #include <linux/pm.h>
> +#include <linux/dmi.h>
>
> #include <asm/hpet.h>
> #include <asm/io.h>
> @@ -48,6 +49,31 @@ static int __init hpet_setup(char* str)
> }
> __setup("hpet=", hpet_setup);
>
> +
> +/* DMI Blacklist for bad HPETs */
> +static int __init dmi_mark_hpet_broken(struct dmi_system_id *d)
> +{
> + printk(KERN_NOTICE "%s detected: HPET does not function.\n",
> + d->ident);
> + boot_hpet_disable = 1;
> + return 0;
> +}
> +
> +/* List of systems that have known HPETproblems */
> +static struct dmi_system_id bad_hpet_dmi_table[] = {
> + {
> + .callback = dmi_mark_hpet_broken,
> + .ident = "Dell OptiPlex 320",
> + .matches = {
> + DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 320"),
> + DMI_MATCH(DMI_BOARD_VENDOR, "Dell Inc."),
> + DMI_MATCH(DMI_BOARD_NAME, "0UT237"),
> + },
> + },
> + {}
> +};
> +
> +
> static inline int is_hpet_capable(void)
> {
> return (!boot_hpet_disable && hpet_address);
> @@ -228,6 +254,8 @@ int __init hpet_enable(void)
> uint64_t hpet_freq;
> u64 tmp;
>
> + dmi_check_system(bad_hpet_dmi_table);
> +
> if (!is_hpet_capable())
> return 0;

The table can be __initdata, can't it?

--- a/arch/i386/kernel/hpet.c~blacklist-dell-optiplex-320-from-using-the-hpet-fix
+++ a/arch/i386/kernel/hpet.c
@@ -60,7 +60,7 @@ static int __init dmi_mark_hpet_broken(s
}

/* List of systems that have known HPETproblems */
-static struct dmi_system_id bad_hpet_dmi_table[] = {
+static struct dmi_system_id __initdata bad_hpet_dmi_table[] = {
{
.callback = dmi_mark_hpet_broken,
.ident = "Dell OptiPlex 320",
@@ -73,7 +73,6 @@ static struct dmi_system_id bad_hpet_dmi
{}
};

-
static inline int is_hpet_capable(void)
{
return (!boot_hpet_disable && hpet_address);
_