Why does using more than six HPS clocks cause routing error?

Description

The global clock network can only route up to six HPS clocks located on the left side of the spine. Exceeding this limit results in an error during routing and placement of clock signals. Example error message as below:

Error: The Fitter failed to find a legal placement for all periphery components

    Info: The following components had the most difficulty being legally placed:

        Info: pin emac1_phy_rxclk_i (15%)

        Info: pin emac2_phy_rxclk_i (15%)

        Info: pin emac0_phy_rxclk_i (15%)

        Info: pin emac2_phy_txclk_i (15%)

        Info: pin emac_ptp_ref_clk (15%)

        Info: pin emac0_phy_txclk_i (15%)

        Info: pin emac1_phy_txclk_i (8%)

Resolution

To resolve this issue, reduce the number of active clocks to six or fewer by disabling unnecessary clocks. Ensure that any disabled clocks align with the user’s design requirements before making changes. In Quartus® Prime Pro version 25.3.1, a legality check has been added, causing the error to appear in the HPS IP component instead of during the fitter stage as example screenshot below.