* timer ticks ?
[not found] <CAGRSmLv1NoKDKu1cJ_g=D7buPSF+9McB6Pts9D5FaMg=nhAp5A@mail.gmail.com>
@ 2017-10-23 23:59 ` David F.
2017-10-24 0:53 ` Ken Taylor
0 siblings, 1 reply; 2+ messages in thread
From: David F. @ 2017-10-23 23:59 UTC (permalink / raw)
To: edk2 developers list
Hi,
Is there a reliable (always available) way to get a timer tick in an
application similar to the old 18.2 per second timer tick from BIOS.
That one was always there, high speed access (no slow access to a RTC)
and the tick count is known (to approx calculate intervals for
polling and other things). In UEFI, EVT_TIMER may not be supported.
GetTime may be slow RTC access. It can be a counter only since
machine was on.
TIA!
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: timer ticks ?
2017-10-23 23:59 ` timer ticks ? David F.
@ 2017-10-24 0:53 ` Ken Taylor
0 siblings, 0 replies; 2+ messages in thread
From: Ken Taylor @ 2017-10-24 0:53 UTC (permalink / raw)
To: David F., edk2 developers list
Hi David,
I think EVT_TIMER is required functionality. Many drivers depend on it.
I know it goes away at runtime, but so do the rest of boot services. There's nothing that can be done about that; even the BIOS timer tick was taken over by all modern operating systems, so it wasn't reliably persistent post boot either.
Regards,
-Ken.
-----Original Message-----
From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of David F.
Sent: Monday, October 23, 2017 4:59 PM
To: edk2 developers list
Subject: [edk2] Fwd: timer ticks ?
Hi,
Is there a reliable (always available) way to get a timer tick in an application similar to the old 18.2 per second timer tick from BIOS.
That one was always there, high speed access (no slow access to a RTC) and the tick count is known (to approx calculate intervals for polling and other things). In UEFI, EVT_TIMER may not be supported.
GetTime may be slow RTC access. It can be a counter only since
machine was on.
TIA!
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^ permalink raw reply [flat|nested] 2+ messages in thread
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2017-10-23 23:59 ` timer ticks ? David F.
2017-10-24 0:53 ` Ken Taylor
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