-----Original Message----- From: Takashi Iwai [mailto:tiwai@suse.de] Sent: Tuesday, November 24, 2015 12:00 AM To: libin.yang@linux.intel.com Cc: alsa-devel@alsa-project.org; mengdong.lin@linux.intel.com; Yang, Libin Subject: Re: [alsa-devel] [RFC V2 PATCH 3/5] ALSA: hda - hdmi dynamically bind PCM to pin when monitor hotplug
On Mon, 23 Nov 2015 15:09:32 +0100, libin.yang@linux.intel.com wrote:
From: Libin Yang libin.yang@linux.intel.com
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@linux.intel.com
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().
Get it.
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; }
OK. I will use the new code.
Regards, Libin
Takashi