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Date: Mon, 5 Dec 2022 10:22:19 +0100
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Subject: Re: [edk2-devel] [PATCH edk2-platforms 2/3] Platform/ARM/JunoPkg: Override PcdTimerPeriod to be 10000
To: devel@edk2.groups.io, quic_rcran@quicinc.com,
 Ard Biesheuvel <ardb+tianocore@kernel.org>,
 Thomas Abraham <thomas.abraham@arm.com>, Sami Mujawar <sami.mujawar@arm.com>
Cc: Rebecca Cran <rebecca@quicinc.com>
References: <20221129135358.136555-1-rebecca@quicinc.com>
 <20221129135358.136555-3-rebecca@quicinc.com>
From: "PierreGondois" <pierre.gondois@arm.com>
In-Reply-To: <20221129135358.136555-3-rebecca@quicinc.com>
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Hello Rebecca,

The default value of PcdTimerPeriod in EmbeddedPkg/EmbeddedPkg.dec
seems to be 100000 (100ns), so 10ms, and other Arm platforms have
set the value to 1000 (100ns), so 100us. I was wondering where you
found the 1ms value ?

Otherwise the other patches look good to me.

Regards,
Pierre


On 11/29/22 14:53, Rebecca Cran via groups.io wrote:
> The PCD PcdTimerPeriod is used in TimerDxe to calculate how many ticks
> to wait between timer interrupts. The default value of 100000 results
> in waiting 10 ms, while the driver wants interrupts to occur every 1ms.
> 
> Override the value of PcdTimerPeriod in ArmJuno.dsc to be 10000.
> 
> Signed-off-by: Rebecca Cran <rebecca@quicinc.com>
> ---
>   Platform/ARM/JunoPkg/ArmJuno.dsc | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/Platform/ARM/JunoPkg/ArmJuno.dsc b/Platform/ARM/JunoPkg/ArmJuno.dsc
> index 9cde4c862651..9b63a8914f03 100644
> --- a/Platform/ARM/JunoPkg/ArmJuno.dsc
> +++ b/Platform/ARM/JunoPkg/ArmJuno.dsc
> @@ -189,6 +189,7 @@ [PcdsFixedAtBuild.common]
>     # ARM Architectural Timer Frequency
>     #
>     gArmTokenSpaceGuid.PcdArmArchTimerFreqInHz|50000000
> +  gEmbeddedTokenSpaceGuid.PcdTimerPeriod|10000
>   
>     gEfiMdeModulePkgTokenSpaceGuid.PcdResetOnMemoryTypeInformationChange|FALSE
>