[PATCH 2/7] ALSA: control: Add power state check commonly for ioctl handlers

[Takashi Iwai]

The card power state check can be better put in the common ioctl
handler, as basically we want to prevent ioctls during the power off
state.  Although this situation won't happen normally any longer (*),
it'll be helpful for catching this for the future implementation like
the faked suspend that is needed for PCI rescan.

(*) Long long time ago, before the proper PM framework was introduced,
it was still possible to reach SNDRV_CTL_IOCTL_POWER ioctl during the
power off state.  This ioctl existed as a main control for the suspend
resume state in the past, but the feature was already dropped along
with the standard PM framework.

Signed-off-by: Takashi Iwai <tiwai at suse.de>
---
 sound/core/control.c        | 3 +++
 sound/core/control_compat.c | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/sound/core/control.c b/sound/core/control.c
index 498e3701514a..c22c3fad0c64 100644
--- a/sound/core/control.c
+++ b/sound/core/control.c
@@ -1772,6 +1772,9 @@ static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg
 	card = ctl->card;
 	if (snd_BUG_ON(!card))
 		return -ENXIO;
+	err = snd_power_wait(card, SNDRV_CTL_POWER_D0);
+	if (err < 0)
+		return err;
 	switch (cmd) {
 	case SNDRV_CTL_IOCTL_PVERSION:
 		return put_user(SNDRV_CTL_VERSION, ip) ? -EFAULT : 0;
diff --git a/sound/core/control_compat.c b/sound/core/control_compat.c
index 1d708aab9c98..d5b562ff237b 100644
--- a/sound/core/control_compat.c
+++ b/sound/core/control_compat.c
@@ -438,6 +438,9 @@ static inline long snd_ctl_ioctl_compat(struct file *file, unsigned int cmd, uns
 	if (snd_BUG_ON(!ctl || !ctl->card))
 		return -ENXIO;
 
+	err = snd_power_wait(ctl->card, SNDRV_CTL_POWER_D0);
+	if (err < 0)
+		return err;
 	switch (cmd) {
 	case SNDRV_CTL_IOCTL_PVERSION:
 	case SNDRV_CTL_IOCTL_CARD_INFO:
-- 
2.26.2