There was previously a lower bound on the value of TickPeriod such that
it couldn't be less than 10 us. However, that was removed from the PI
Specification in the 1.0 errata released in 2007. From the revision
history:

"M171 Remove 10 us lower bound restriction for the TickPeriod in the
Metronome"

Update the documentation of TickPeriod in MetronomeDxe/Metronome.c to
remove mention of the lower bound.

Signed-off-by: Rebecca Cran <rebecca@...>
---
EmbeddedPkg/MetronomeDxe/Metronome.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/EmbeddedPkg/MetronomeDxe/Metronome.c b/EmbeddedPkg/MetronomeDxe/Metronome.c
index a0892315827f..63db6d513969 100644
--- a/EmbeddedPkg/MetronomeDxe/Metronome.c
+++ b/EmbeddedPkg/MetronomeDxe/Metronome.c
@@ -43,10 +43,9 @@ WaitForTick (

@param TickPeriod
The period of platform's known time source in 100 nS units.
- This value on any platform must be at least 10 uS, and must not
- exceed 200 uS. The value in this field is a constant that must
- not be modified after the Metronome architectural protocol is
- installed. All consumers must treat this as a read-only field.
+ This value on any platform must not exceed 200 uS. The value in this field
+ is a constant that must not be modified after the Metronome architectural
+ protocol is installed. All consumers must treat this as a read-only field.

**/
EFI_METRONOME_ARCH_PROTOCOL gMetronome = {
--
2.30.2

On Tue, Nov 29, 2022 at 05:40:56 -0700, Rebecca Cran wrote:

There was previously a lower bound on the value of TickPeriod such that
it couldn't be less than 10 us. However, that was removed from the PI
Specification in the 1.0 errata released in 2007. From the revision
history:

"M171 Remove 10 us lower bound restriction for the TickPeriod in the
Metronome"

Update the documentation of TickPeriod in MetronomeDxe/Metronome.c to
remove mention of the lower bound.

Signed-off-by: Rebecca Cran <rebecca@...>

Reviewed-by: Leif Lindholm <quic_llindhol@...>

I updated the subject line to pass patchcheck.py and pushed it as
8aff08c.

Thanks!

Diffing this file against the MdeModulePkg original, this seems
inferior in every way other than possibly reducing the risk of
counter overflow on 32-bit architectures.

I will follow up with a patch that adds a #warning on all non-32-bit
architectures.

/
Leif

---
EmbeddedPkg/MetronomeDxe/Metronome.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/EmbeddedPkg/MetronomeDxe/Metronome.c b/EmbeddedPkg/MetronomeDxe/Metronome.c
index a0892315827f..63db6d513969 100644
--- a/EmbeddedPkg/MetronomeDxe/Metronome.c
+++ b/EmbeddedPkg/MetronomeDxe/Metronome.c
@@ -43,10 +43,9 @@ WaitForTick (

@param TickPeriod
The period of platform's known time source in 100 nS units.
- This value on any platform must be at least 10 uS, and must not
- exceed 200 uS. The value in this field is a constant that must
- not be modified after the Metronome architectural protocol is
- installed. All consumers must treat this as a read-only field.
+ This value on any platform must not exceed 200 uS. The value in this field
+ is a constant that must not be modified after the Metronome architectural
+ protocol is installed. All consumers must treat this as a read-only field.

**/
EFI_METRONOME_ARCH_PROTOCOL gMetronome = {
--
2.30.2