brcm2708: switch to linux 4.4 and update patches

[openwrt/svn-archive/archive.git] / target / linux / brcm2708 / patches-4.4 / 0134-bcm2835-only-allow-stereo-if-analogue-jack-is-select.patch

diff --git a/target/linux/brcm2708/patches-4.4/0134-bcm2835-only-allow-stereo-if-analogue-jack-is-select.patch b/target/linux/brcm2708/patches-4.4/0134-bcm2835-only-allow-stereo-if-analogue-jack-is-select.patch
new file mode 100644 (file)
index 0000000..e7bdfc7
--- /dev/null
+++ b/target/linux/brcm2708/patches-4.4/0134-bcm2835-only-allow-stereo-if-analogue-jack-is-select.patch
@@ -0,0 +1,62 @@
+From 22606ad9e0d809ce0d4e12b51d5b4c6507f89c2d Mon Sep 17 00:00:00 2001
+From: wm4 <wm4@nowhere>
+Date: Wed, 13 Jan 2016 19:44:24 +0100
+Subject: [PATCH 134/156] bcm2835: only allow stereo if analogue jack is
+ selected
+
+Sending more than 2 channels to videocore while outputting to analogue
+mysteriously outputs heavy artifacts. So just paint it over with a
+hack: if analogue is explicitly selected as destination, do not
+reporting support for anything other than stereo.
+
+I'm not sure how to deal with the auto case (destination 0). There's
+probably way to retrieve this and even to listen to plug events, but
+I didn't find one yet, and it's probably not worth the trouble. Just
+don't use this setting, I guess. Unless you like noise.
+
+Changing the setting while an audio stream is active also doesn't
+work properly. We could probably interrupt running streams by
+returning ENODEV or using kernel hotplug stuff (maybe), but that
+also doesn't seem worth the trouble.
+---
+ sound/arm/bcm2835-ctl.c | 12 ++++++++++++
+ 1 file changed, 12 insertions(+)
+
+--- a/sound/arm/bcm2835-ctl.c
++++ b/sound/arm/bcm2835-ctl.c
+@@ -423,9 +423,16 @@ static struct cea_channel_speaker_alloca
+ { .ca_index = 0x31,  .speakers = { FRW,  FLW,  RR,  RL,  FC,  LFE,  FR,  FL } },
+ };
+ 
++static int uses_analogue(bcm2835_chip_t *chip)
++{
++      return chip->dest == 1;
++}
++
+ static int snd_bcm2835_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);
++      bcm2835_chip_t *chip = info->private_data;
+       unsigned int __user *dst;
+       int count = 0;
+       int i;
+@@ -442,6 +449,9 @@ static int snd_bcm2835_chmap_ctl_tlv(str
+               int chs_bytes;
+               int c;
+ 
++              if (i > 0 && uses_analogue(chip))
++                      break;
++
+               for (c = 0; c < 8; c++) {
+                       if (ch->speakers[c])
+                               num_chs++;
+@@ -552,6 +562,8 @@ static int snd_bcm2835_chmap_ctl_put(str
+               int matches = 1;
+               int cur = 0;
+               int x;
++              if (i > 0 && uses_analogue(chip))
++                      break;
+               memset(remap, 0, sizeof(remap));
+               for (x = 0; x < substream->runtime->channels; x++) {
+                       int sp = ucontrol->value.integer.value[x];