On Mon, 23 Nov 2015 15:09:32 +0100,
libin.yang@xxxxxxxxxxxxxxx wrote:
>
> From: Libin Yang <libin.yang@xxxxxxxxxxxxxxx>
>
> Dynamically bind/unbind the PCM to pin when HDMI/DP monitor hotplug.
>
> When monitor is connected, find a proper PCM for the monitor.
> When monitor is disconnected, unbind the PCM from the pin.
You must have some strategy about binding. Please tell the story
behind the scene, too.
>
> Signed-off-by: Libin Yang <libin.yang@xxxxxxxxxxxxxxx>
> ---
> sound/pci/hda/patch_hdmi.c | 82 ++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 82 insertions(+)
>
> diff --git a/sound/pci/hda/patch_hdmi.c b/sound/pci/hda/patch_hdmi.c
> index de22ac2..bcc2a90 100644
> --- a/sound/pci/hda/patch_hdmi.c
> +++ b/sound/pci/hda/patch_hdmi.c
> @@ -72,6 +72,8 @@ struct hdmi_spec_per_cvt {
>
> struct hdmi_spec_per_pin {
> hda_nid_t pin_nid;
> + /* pin idx, different device entries on the same pin use the same idx */
> + int pin_nid_idx;
> int num_mux_nids;
> hda_nid_t mux_nids[HDA_MAX_CONNECTIONS];
> int mux_idx;
> @@ -83,6 +85,7 @@ struct hdmi_spec_per_pin {
> struct delayed_work work;
> struct snd_kcontrol *eld_ctl;
> struct hda_pcm *pcm; /* pointer to spec->pcm_rec[n] dynamically*/
> + int pcm_idx; /* which pcm is attached. -1 means no pcm is attached */
> int repoll_count;
> bool setup; /* the stream has been set up by prepare callback */
> int channels; /* current number of channels */
> @@ -136,6 +139,7 @@ struct hdmi_spec {
> struct snd_array pins; /* struct hdmi_spec_per_pin */
> struct hda_pcm *pcm_rec[16];
> struct mutex pcm_lock;
> + unsigned long pcm_bitmap;
> int pcm_used; /* counter of pcm_rec[] */
> unsigned int channels_max; /* max over all cvts */
>
> @@ -1663,6 +1667,70 @@ static int hdmi_read_pin_conn(struct hda_codec *codec, int pin_idx)
> return 0;
> }
>
> +static int get_preferred_pcm_slot(struct hdmi_spec *spec,
> + struct hdmi_spec_per_pin *per_pin)
> +{
> + if ((spec->pcm_bitmap & (1 << per_pin->pin_nid_idx)) == 0)
Use test_bit().
> + return per_pin->pin_nid_idx;
> + return -1;
> +}
> +
> +static int hdmi_find_pcm_slot(struct hdmi_spec *spec,
> + struct hdmi_spec_per_pin *per_pin)
> +{
> + int slot;
> + int i;
> +
> + /* try the prefer PCM */
> + slot = get_preferred_pcm_slot(spec, per_pin);
> + if (slot != -1)
> + return slot;
> +
> + /* have a second try */
> + for (i = spec->num_pins; i < spec->pcm_used; i++) {
> + if ((spec->pcm_bitmap & (1 << i)) == 0)
Ditto.
> + return i;
> + }
> +
> + /* the last try */
> + for (i = 0; i < spec->pcm_used; i++) {
> + if ((spec->pcm_bitmap & (1 << i)) == 0)
Ditto.
> + return i;
> + }
> + return -ENODEV;
I think you don't need to split get_preferred_pcm_slot().
It's a function that is called only from here, and it's even better to
be open-coded. Then you can see the code flow more easily.
(Also, you may notice that the last loop doesn't go all, but just up
to num_pins, by looking through the code closely.)
static int hdmi_find_pcm_slot(struct hdmi_spec *spec,
struct hdmi_spec_per_pin *per_pin)
{
int i;
/* try the prefer PCM */
if (!test_bit(per_pin->pin_nid_idx, &spec->pcm_bitmap))
return per_pin->pin_nid_idx;
/* have a second try; check the "reserved area" over num_pins */
for (i = spec->num_pins; i < spec->pcm_used; i++)
if (!test_bit(i, &spec->pcm_bitmap))
return i;
/* the last try; check the empty slots in pins */
for (i = 0; i < spec->num_pins; i++)
if (!test_bit(i, &spec->pcm_bitmap))
return i;
return -EBUSY;
}
Takashi
_______________________________________________
Alsa-devel mailing list
Alsa-devel@xxxxxxxxxxxxxxxx
http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
