diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.4/0134-bcm2835-only-allow-stereo-if-analogue-jack-is-select.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.4/0134-bcm2835-only-allow-stereo-if-analogue-jack-is-select.patch | 62 |
1 files changed, 62 insertions, 0 deletions
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 index 0000000000..e7bdfc7a3c --- /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]; |