From 5b43df8b4c1a7f0c3fbf793c9566068e6b1e570c Mon Sep 17 00:00:00 2001 From: Shawn Lin Date: Fri, 23 Feb 2018 16:47:25 +0800 Subject: [PATCH] mmc: dw_mmc: Avoid accessing registers in runtime suspended state cat /sys/kernel/debug/mmc0/regs will hang up the system since it's in runtime suspended state, so the genpd and biu_clk is off. This patch fixes this problem by calling pm_runtime_get_sync to wake it up before reading the registers. Fixes: e9ed8835e990 ("mmc: dw_mmc: add runtime PM callback") Cc: Signed-off-by: Shawn Lin Reviewed-by: Jaehoon Chung Signed-off-by: Ulf Hansson --- drivers/mmc/host/dw_mmc.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c index a850f8d..d9b4ace 100644 --- a/drivers/mmc/host/dw_mmc.c +++ b/drivers/mmc/host/dw_mmc.c @@ -165,6 +165,8 @@ static int dw_mci_regs_show(struct seq_file *s, void *v) { struct dw_mci *host = s->private; + pm_runtime_get_sync(host->dev); + seq_printf(s, "STATUS:\t0x%08x\n", mci_readl(host, STATUS)); seq_printf(s, "RINTSTS:\t0x%08x\n", mci_readl(host, RINTSTS)); seq_printf(s, "CMD:\t0x%08x\n", mci_readl(host, CMD)); @@ -172,6 +174,8 @@ static int dw_mci_regs_show(struct seq_file *s, void *v) seq_printf(s, "INTMASK:\t0x%08x\n", mci_readl(host, INTMASK)); seq_printf(s, "CLKENA:\t0x%08x\n", mci_readl(host, CLKENA)); + pm_runtime_put_autosuspend(host->dev); + return 0; } -- 2.7.4