On Thu, Feb 07, 2019 at 11:52:11PM +0100, Jonathan Neuschäfer wrote: > However, as soon as the mmc driver (sdhci-esdhc-imx.c) disables clk_per > in sdhci_esdhc_runtime_suspend[2], the whole system locks up in some way. I've traced clk prepare/unprepare/enable/disable calls and got this right before it hangs: [ 1.280981] sdhci_esdhc_runtime_suspend: unprepare clk_per [ 1.283356] clk_core_unprepare esdhc1_per_gate [ 1.285191] clk_core_unprepare esdhc_a_podf [ 1.286881] clk_core_unprepare esdhc_a_pred [ 1.288568] clk_core_unprepare esdhc_a_sel [ 1.290220] clk_core_unprepare pll2_sw I suspect that there is a dependency on pll2_sw that is not represented in the imx5 clock driver. I'm comparing it to the Reference Manual now. Thanks, Jonathan Neuschäfer