@@ -3924,15 +3924,12 @@ The scheme of the real suspend job is as follows.
2. Call :c:func:`snd_power_change_state()` with
``SNDRV_CTL_POWER_D3hot`` to change the power status.
-3. Call :c:func:`snd_pcm_suspend_all()` to suspend the running
- PCM streams.
-
-4. If AC97 codecs are used, call :c:func:`snd_ac97_suspend()` for
+3. If AC97 codecs are used, call :c:func:`snd_ac97_suspend()` for
each codec.
-5. Save the register values if necessary.
+4. Save the register values if necessary.
-6. Stop the hardware if necessary.
+5. Stop the hardware if necessary.
A typical code would be like:
@@ -3946,12 +3943,10 @@ A typical code would be like:
/* (2) */
snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
/* (3) */
- snd_pcm_suspend_all(chip->pcm);
- /* (4) */
snd_ac97_suspend(chip->ac97);
- /* (5) */
+ /* (4) */
snd_mychip_save_registers(chip);
- /* (6) */
+ /* (5) */
snd_mychip_stop_hardware(chip);
return 0;
}
@@ -3994,13 +3989,9 @@ A typical code would be like:
return 0;
}
-As shown in the above, it's better to save registers after suspending
-the PCM operations via :c:func:`snd_pcm_suspend_all()` or
-:c:func:`snd_pcm_suspend()`. It means that the PCM streams are
-already stopped when the register snapshot is taken. But, remember that
-you don't have to restart the PCM stream in the resume callback. It'll
-be restarted via trigger call with ``SNDRV_PCM_TRIGGER_RESUME`` when
-necessary.
+Note that, at the time this callback gets called, the PCM stream has
+been already suspended via its own PM ops calling
+:c:func:`snd_pcm_suspend_all()` internally.
OK, we have all callbacks now. Let's set them up. In the initialization
of the card, make sure that you can get the chip data from the card
The PCM suspend procedure was changed for drivers, so that they don't have to call snd_pcm_suspend*() in each callback any longer. Update the documentation to adapt the changes. Signed-off-by: Takashi Iwai <tiwai@suse.de> --- .../kernel-api/writing-an-alsa-driver.rst | 25 ++++++------------- 1 file changed, 8 insertions(+), 17 deletions(-)