path: root/fs/debugfs
diff options
authorGeert Uytterhoeven <>2020-02-11 19:18:55 +0100
committerHerbert Xu <>2020-02-22 09:25:42 +0800
commit30332eeefec8f83afcea00c360f99ef64b87f220 (patch)
treef1d07f6fe23cb002d66933b9cc35e3c626d03db6 /fs/debugfs
parent9e00df7156e45e42c695ffc596b4bf1328d00516 (diff)
debugfs: regset32: Add Runtime PM support
Hardware registers of devices under control of power management cannot be accessed at all times. If such a device is suspended, register accesses may lead to undefined behavior, like reading bogus values, or causing exceptions or system lock-ups. Extend struct debugfs_regset32 with an optional field to let device drivers specify the device the registers in the set belong to. This allows debugfs_show_regset32() to make sure the device is resumed while its registers are being read. Signed-off-by: Geert Uytterhoeven <> Reviewed-by: Niklas Söderlund <> Reviewed-by: Greg Kroah-Hartman <> Acked-by: Rafael J. Wysocki <> Signed-off-by: Herbert Xu <>
Diffstat (limited to 'fs/debugfs')
1 files changed, 8 insertions, 0 deletions
diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
index 634b09d18b77..204734f8d1c6 100644
--- a/fs/debugfs/file.c
+++ b/fs/debugfs/file.c
@@ -18,6 +18,7 @@
#include <linux/slab.h>
#include <linux/atomic.h>
#include <linux/device.h>
+#include <linux/pm_runtime.h>
#include <linux/poll.h>
#include <linux/security.h>
@@ -1060,7 +1061,14 @@ static int debugfs_show_regset32(struct seq_file *s, void *data)
struct debugfs_regset32 *regset = s->private;
+ if (regset->dev)
+ pm_runtime_get_sync(regset->dev);
debugfs_print_regs32(s, regset->regs, regset->nregs, regset->base, "");
+ if (regset->dev)
+ pm_runtime_put(regset->dev);
return 0;