On Thu, 29 Aug 2013 12:18:14 -0400
Joseph Salisbury <joseph.salisbury@xxxxxxxxxxxxx> wrote:
> On 08/14/2013 05:11 PM, Linus Torvalds wrote:
> > On Wed, Aug 14, 2013 at 9:38 AM, Jesse Barnes <jbarnes@xxxxxxxxxxxxxxxx> wrote:
> >> Linus, you may want to pick this up directly, as I'm not sure if
> >> Matthew is still looking after the x86 drivers these days.
> > Can't we make the simpler patch be to just not spam the logs? Do it
> > once, and forget about it. Maybe make the timeouts long enough to make
> > sure that there are no other downsides from having the driver
> > occasionally testing if it's back?
> >
> > I *detest* hardware-specific blacklists. They are impossible to
> > maintain, and we've had the situation more than once that we fixed the
> > real bug that caused the blacklist in the first place, but the entry
> > stays around because nobody knows/cares/tests it.
> >
> > Linus
> Hi Jesse,
>
> What are your thoughts on alternatives to using a blacklist? Is there a
> bit we can read to determine if IPS is supported on a platform?
>
> If not, can we do something like the following? Basically increase the
> timeout to 30 seconds then return an error from the monitor if there was
> no update in that time:
>
> diff --git a/drivers/platform/x86/intel_ips.c
> b/drivers/platform/x86/intel_ips.c
> index 18dcb58..a2391f7 100644
> --- a/drivers/platform/x86/intel_ips.c
> +++ b/drivers/platform/x86/intel_ips.c
> @@ -1095,8 +1095,15 @@ static int ips_monitor(void *data)
> cur_seqno = (thm_readl(THM_ITV) & ITV_ME_SEQNO_MASK) >>
> ITV_ME_SEQNO_SHIFT;
> if (cur_seqno == last_seqno &&
> - time_after(jiffies, seqno_timestamp + HZ)) {
> - dev_warn(&ips->dev->dev, "ME failed to update
> for more than 1s, likely hung\n");
> + time_after(jiffies, seqno_timestamp + (HZ*30))) {
> + /* It's been 30s. ME is likely hung. Print
> message and return. */
> + dev_warn(&ips->dev->dev, "ME failed to update
> for more than 30s, likely hung so exiting\n");
> + del_timer_sync(&timer);
> + destroy_timer_on_stack(&timer);
> +
> + dev_dbg(&ips->dev->dev, "ips-monitor thread
> stopped\n");
> + return -1;
> +
> } else {
> seqno_timestamp = get_jiffies_64();
> last_seqno = cur_seqno;
>
> There may be more to include such as restarting the monitor later to see
> if the ME ever came back, just looking for other ideas and/or suggestions.
Yeah, something like that might be ok. But ideally we'd detect whether
an ME was present at all like Matthew says.
I'm not sure how to do that, but maybe Anas does (or can point us to
someone else who would know).
--
Jesse Barnes, Intel Open Source Technology Center
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