Hi Thomas, [...] > struct mvebu_mbus_state { > void __iomem *mbuswins_base; > void __iomem *sdramwins_base; > + void __iomem *mbusbridge_base; Here you store the information about the availability of the register needed for suspend/resume ... [...] > +static int mvebu_mbus_suspend(void) > +{ > + struct mvebu_mbus_state *s = &mbus_state; > + int win; > + > + for (win = 0; win < s->soc->num_wins; win++) { > + void __iomem *addr = s->mbuswins_base + > + s->soc->win_cfg_offset(win); > + > + s->wins[win].base = readl(addr + WIN_BASE_OFF); > + s->wins[win].ctrl = readl(addr + WIN_CTRL_OFF); > + > + if (win >= s->soc->num_remappable_wins) > + continue; > + > + s->wins[win].remap_lo = readl(addr + WIN_REMAP_LO_OFF); > + s->wins[win].remap_hi = readl(addr + WIN_REMAP_HI_OFF); > + } > + > + if (s->mbusbridge_base) { > + s->mbus_bridge_ctrl = readl(s->mbusbridge_base + > + MBUS_BRIDGE_CTRL_OFF); > + s->mbus_bridge_base = readl(s->mbusbridge_base + > + MBUS_BRIDGE_BASE_OFF); > + } ... so here could you exit with an error if the register is not available. Then it would prevent to enter in suspend instead of crashing the system. Thanks, Gregory -- Gregory Clement, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html