[Linux-kernel-mentees] Any other ways to debug GPIO interrupt controller (pinctrl-amd) for broken touchpads of a new laptop model?
andy.shevchenko at gmail.com
Tue Nov 3 10:49:09 UTC 2020
On Tue, Nov 3, 2020 at 12:12 PM Hans de Goede <hdegoede at redhat.com> wrote:
> On 11/3/20 1:05 AM, Coiby Xu wrote:
> > On Tue, Oct 27, 2020 at 11:09:11AM +0100, Hans de Goede wrote:
> >  https://lore.kernel.org/patchwork/comment/1522675/
> This is a case where Andy is obviously right and you should just use the
> higher precision "unit = 15625" value (except probably that is wrong too,
> see below).
> We have had similar issues with the docs for getting the TSC frequency
> on some Intel chips, where the docs said 16.6 MHz for a certain register
> value, where what they meant was 100/6 MHz which really is significantly
> different. This was leading to a time drift of 5 minutes / day on non
> networked (so no NTP) Linux systems.
> I think this is what Andy was referring to when he wrote:
> "What the heck with HW companies! (Just an emotion based on the experience)"
> Actually all the values look somewhat suspect. The comment:
> > Debounce Debounce Timer Max
> > TmrLarge TmrOutUnit Unit Debounce
> > Time
> > 0 0 61 usec (2 RtcClk) 976 usec
> > 0 1 244 usec (8 RtcClk) 3.9 msec
> > 1 0 15.6 msec (512 RtcClk) 250 msec
> > 1 1 62.5 msec (2048 RtcClk) 1 sec
> Helpfully gives the values in RtcClks. A typical RTC clock crystal
> is 32 KHz which gives us 31.25 usec per tick, so I would expect the
> values to be:
I guess you are mistaken here. Usual frequency for RTC is 32.768kHz
, which gives more or less above values
(just google: rtc clock frequency)
With Best Regards,
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