Subject: Re: [PATCH] amd-xgbe: fix PTP addend overflow causing frozen clock

From: [email-masked]
Date: Sat, 02 May 2026 18:20:16 +0000

Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <[email-masked]>:

On Wed, 29 Apr 2026 14:54:14 -0700 you wrote:
> From: Gregory Fuchedgi <[email-masked]>
> 
> XGBE_PTP_ACT_CLK_FREQ and XGBE_V2_PTP_ACT_CLK_FREQ were 10x too
> large (500MHz/1GHz instead of 50MHz/100MHz), causing the computed
> addend to overflow the 32-bit tstamp_addend. In the general case
> this would result in the clock advancing at the wrong rate. For v2
> (PCI), ptpclk_rate is hardcoded to 125MHz, so the addend formula
> (ACT_CLK_FREQ << 32) / ptpclk_rate yields exactly 8 * 2^32, and
> when stored to the 32-bit tstamp_addend the value is zero. With
> addend = 0 the hardware accumulator never overflows and the PTP
> clock is fully stopped. For v1 (platform), ptpclk_rate is read from
> ACPI/DT so the exact overflow behavior depends on the
> firmware-reported frequency.
> 
> [...]

Here is the summary with links:
  - amd-xgbe: fix PTP addend overflow causing frozen clock
    https://git.kernel.org/netdev/net/c/383d0fb89469

You are awesome, thank you!
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