Re: [alsa-devel] [PATCH v2] ALSA: hda - Update chmap tlv to report sink's capability

On Fri, 01 Apr 2016 12:18:51 +0200, Subhransu S. Prusty wrote:

The existing TLV callback implementation copies all of the cea_channel_speaker_allocation map table to the TLV container irrespective of what is reported by sink. This is of little use to the userspace application.

With this patch, it parses the spk_alloc block as queried from the ELD, and copies only the corresponding channel map from the cea channel speaker allocation table. Thus the user can parse the TLV container to identify sink's capability and set the channel map accordingly.

It shouldn't impact the behavior in AMD chipset, as this makes use of already parsed spk alloc block to calculate the channel map.

Signed-off-by: Subhransu S. Prusty subhransu.s.prusty@intel.com Signed-off-by: Vinod Koul vinod.koul@intel.com

---

changes in v2: Updated the commit message to make it more understandable.

Thanks, I'm now rereading the patch after realizing what's doing. So some questions:

include/sound/hda_chmap.h | 2 ++ sound/hda/hdmi_chmap.c | 90 +++++++++++++++++++++++++++++----------------- sound/pci/hda/patch_hdmi.c | 13 +++++++ 3 files changed, 72 insertions(+), 33 deletions(-)

diff --git a/include/sound/hda_chmap.h b/include/sound/hda_chmap.h index e20d219..babd445 100644 --- a/include/sound/hda_chmap.h +++ b/include/sound/hda_chmap.h @@ -36,6 +36,8 @@ struct hdac_chmap_ops { int (*chmap_validate)(struct hdac_chmap *hchmap, int ca, int channels, unsigned char *chmap);

• int (*get_spk_alloc)(struct hdac_device *hdac, int pcm_idx);
• void (*get_chmap)(struct hdac_device *hdac, int pcm_idx, unsigned char *chmap); void (*set_chmap)(struct hdac_device *hdac, int pcm_idx,

diff --git a/sound/hda/hdmi_chmap.c b/sound/hda/hdmi_chmap.c index d7ec862..9406203 100644 --- a/sound/hda/hdmi_chmap.c +++ b/sound/hda/hdmi_chmap.c @@ -625,13 +625,40 @@ static void hdmi_cea_alloc_to_tlv_chmap(struct hdac_chmap *hchmap, WARN_ON(count != channels); }

+static struct hdac_cea_channel_speaker_allocation *get_cap_from_spk_alloc(

• 					int spk_alloc)
  

+{

• int i, spk_mask = 0;
• if (!spk_alloc)

• return &channel_allocations[0];
  

• for (i = 0; i < ARRAY_SIZE(eld_speaker_allocation_bits); i++) {

• if (spk_alloc & (1 << i))
  

• 	spk_mask |= eld_speaker_allocation_bits[i];
  

• }
• /* Get num channels using spk mask */
• for (i = 0; i < ARRAY_SIZE(channel_allocations); i++) {

• if ((spk_mask & channel_allocations[i].spk_mask) == spk_mask)
  

• 	return &channel_allocations[i];
  

• }
• return &channel_allocations[0];

+}

This function returns the channel allocation corresponding to the given speakers, right? Don't you need to pass the number of channels? (The question is relevant with below.)

static int hdmi_chmap_ctl_tlv(struct snd_kcontrol *kcontrol, int op_flag, unsigned int size, unsigned int __user *tlv) { struct snd_pcm_chmap *info = snd_kcontrol_chip(kcontrol); struct hdac_chmap *chmap = info->private_data;

• int pcm_idx = kcontrol->private_value; unsigned int __user *dst;

• int chs, count = 0;

• int chs, count = 0, chs_bytes;

• int type;

• unsigned int tlv_chmap[8];

• int spk_alloc;

• struct hdac_cea_channel_speaker_allocation *cap;

  if (size < 8) return -ENOMEM;

@@ -639,40 +666,37 @@ static int hdmi_chmap_ctl_tlv(struct snd_kcontrol *kcontrol, int op_flag, return -EFAULT; size -= 8; dst = tlv + 2;

• for (chs = 2; chs <= chmap->channels_max; chs++) {

• int i;
  

• struct hdac_cea_channel_speaker_allocation *cap;
  

• cap = channel_allocations;
  

• for (i = 0; i < ARRAY_SIZE(channel_allocations); i++, cap++) {
  

• 	int chs_bytes = chs * 4;
  

• 	int type = chmap->ops.chmap_cea_alloc_validate_get_type(
  

• 						chmap, cap, chs);
  

• 	unsigned int tlv_chmap[8];
  

• 	if (type < 0)
  

• 		continue;
  

• 	if (size < 8)
  

• 		return -ENOMEM;
  

• 	if (put_user(type, dst) ||
  

• 	    put_user(chs_bytes, dst + 1))
  

• 		return -EFAULT;
  

• 	dst += 2;
  

• 	size -= 8;
  

• 	count += 8;
  

• 	if (size < chs_bytes)
  

• 		return -ENOMEM;
  

• 	size -= chs_bytes;
  

• 	count += chs_bytes;
  

• 	chmap->ops.cea_alloc_to_tlv_chmap(chmap, cap,
  

• 				tlv_chmap, chs);
  

• 	if (copy_to_user(dst, tlv_chmap, chs_bytes))
  

• 		return -EFAULT;
  

• 	dst += chs;
  

• }
  

• }

• if (size < 8)

• return -ENOMEM;
  

• spk_alloc = chmap->ops.get_spk_alloc(chmap->hdac, pcm_idx);
• cap = get_cap_from_spk_alloc(spk_alloc);
• chs = cap->channels;
• chs_bytes = chs * 4;
• type = chmap->ops.chmap_cea_alloc_validate_get_type(chmap, cap, chs);
• if (type < 0)

• return -ENODEV;
  

• if (put_user(type, dst) ||

•    put_user(chs_bytes, dst + 1))
  

• return -EFAULT;
  

• dst += 2;
• size -= 8;
• count += 8;
• if (size < chs_bytes)

• return -ENOMEM;
  

• count += chs_bytes;
• chmap->ops.cea_alloc_to_tlv_chmap(chmap, cap, tlv_chmap, chs);
• if (copy_to_user(dst, tlv_chmap, chs_bytes))

• return -EFAULT;
  

• if (put_user(count, tlv + 1)) return -EFAULT;
• return 0;

So, this change means that TLV returns only a single channel map corresponding to the given speaker bits? This doesn't sound right. TLV should return the all possible channel maps the device are capable of. A device with four channels can drive also two channels streams, too, for example.

Takashi