On 17 July 2016 at 19:13, Ezequiel Garcia <ezequiel@xxxxxxxxxxxxxxxxxxxx> wrote:
> Hi Guenter,
>
> Thanks a lot for the quick reply.
>
> On 16 Jul 10:18 AM, Guenter Roeck wrote:
>> On 07/15/2016 04:21 PM, Ezequiel Garcia wrote:
>> > Hi everyone,
>> >
>> > A large portion of my intel-based products are suffering from
>> > a nasty hardware freeze [1], and so I'm currently working this around
>> > enabling the iTCO watchdog -- which in any case, it's a good idea
>> > to have enabled.
>> >
>> > So, it would be interesting to find out on each boot if the machine was
>> > rebooted due to a watchdog timeout, but so far I'm not having any luck.
>> >
>> > As per Intel's appnote [2] the BIOS should update the WDDT ACPI table,
>> > so I added something like this to the iTCO driver:
>> >
>> > status = acpi_get_table(ACPI_SIG_WDDT, 1,
>> > (struct acpi_table_header **) &buf);
>> > if (ACPI_FAILURE(status) || buf->header.length < sizeof(*buf)) {
>> > pr_err(FW_BUG "failed to get WDDT ACPI table\n");
>> > return;
>> > }
>> >
>> > But it doesn't find the table. Strangely, reading TCO1_STS
>> > and TCO2_STS always gives 0x0.
>> >
>>
>> That sounds like either the BIOS resets those bits, or the reboots
>> are not caused by the watchdog. Are you sure that you see reboots
>> that are caused by the watchdog ?
>>
>
> Yes, I'm testing my patch forcing watchdog reboots. At least on my i5
> development machine, I haven't found any way of querying the reboot
> reason. I'm not even sure this is supposed to work.
>
> I'll see if I can test on other intel machines with TCO watchdogs.
>
FWIW, repeated this test on a Bay Trail SoC TCO device, with no luck.
Thanks,
--
Ezequiel García, VanguardiaSur
www.vanguardiasur.com.ar
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