[PATCH 6/9] drm/i915/display: iterare through channels if no feasible frequencies

[Vinod Govindapillai]

For a pipe configuration, if no supported audio frequencies are
found, then start reducing the audio channels and try assess the
sad audio frequency list again.

Bspec: 67768
Signed-off-by: Vinod Govindapillai <vinod.govindapil...@intel.com>
---
 drivers/gpu/drm/i915/display/intel_audio.c | 32 ++++++++++++++++------
 1 file changed, 24 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_audio.c 
b/drivers/gpu/drm/i915/display/intel_audio.c
index e84101ef9531..14fabbcbf5da 100644
--- a/drivers/gpu/drm/i915/display/intel_audio.c
+++ b/drivers/gpu/drm/i915/display/intel_audio.c
@@ -766,16 +766,28 @@ static void intel_audio_compute_sad(struct 
drm_i915_private *i915,
                                    int avail_overhead, int req_overhead,
                                    struct cea_sad *sad)
 {
-       u8 sad_channels = sad->channels + 1;
+       u8 channels;
        u8 sad_freq;
 
-       sad_freq = intel_audio_get_pruned_audfreq(i915, line_freq_khz,
-                                                 hblank_slots_lanes,
-                                                 avail_overhead,
-                                                 req_overhead, sad_channels,
-                                                 sad->freq);
+       /*
+        * If we don't find any supported audio frequencies for a channel,
+        * reduce the channel and try
+        */
+       for (channels = sad->channels + 1; channels >= 1; channels--) {
+               sad_freq = intel_audio_get_pruned_audfreq(i915, line_freq_khz,
+                                                         hblank_slots_lanes,
+                                                         avail_overhead,
+                                                         req_overhead,
+                                                         channels,
+                                                         sad->freq);
+
+               /* Supported frequencies exist! No need to proceed further */
+               if (sad_freq)
+                       break;
+       }
 
        sad->freq = sad_freq;
+       sad->channels = channels ? channels - 1 : 0;
 }
 
 bool intel_audio_compute_eld_config(struct drm_connector_state *conn_state,
@@ -793,19 +805,23 @@ bool intel_audio_compute_eld_config(struct 
drm_connector_state *conn_state,
        for (int i = 0; i < drm_eld_sad_count(eld); i++) {
                struct cea_sad sad;
                u8 sad_freq;
+               u8 sad_channels;
 
                if (drm_eld_sad_get(eld, i, &sad))
                        continue;
 
                sad_freq = sad.freq;
+               sad_channels = sad.channels;
                intel_audio_compute_sad(i915, line_freq_khz,
                                        hblank_slots_lanes,
                                        avail_overhead, req_overhead, &sad);
 
                /* Update the eld with new sad data if any changes in the list 
*/
-               if (sad_freq != sad.freq) {
+               if (sad_freq != sad.freq || sad_channels != sad.channels) {
                        drm_eld_sad_set(eld, i, &sad);
-                       drm_dbg_kms(&i915->drm, "sad updated. Pruned freq list: 
0x%x\n", sad.freq);
+                       drm_dbg_kms(&i915->drm,
+                                   "SAD updated. Freq: 0x%x(0x%x) Channels: 
%d(%d)\n",
+                                   sad.freq, sad_freq, sad.channels, 
sad_channels);
                }
        }
 
-- 
2.34.1