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freifunkist-firmware/target/linux/brcm2708/patches-4.14/950-0410-bcm2835-interpolat...

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3.7 KiB

brcm2708: add kernel 4.14 support Patch generation process: - rebase rpi/rpi-4.14.y on v4.14.89 from linux-stable - git format-patch v4.14.89 Patches skipped during rebase: - lan78xx: Read MAC address from DT if present - lan78xx: Enable LEDs and auto-negotiation - Revert "softirq: Let ksoftirqd do its job" - sc16is7xx: Fix for multi-channel stall - lan78xx: Ignore DT MAC address if already valid - lan78xx: Simple patch to prevent some crashes - tcp_write_queue_purge clears all the SKBs in the write queue - Revert "lan78xx: Simple patch to prevent some crashes" - lan78xx: Connect phy early - Arm: mm: ftrace: Only set text back to ro after kernel has been marked ro - Revert "Revert "softirq: Let ksoftirqd do its job"" - ASoC: cs4265: SOC_SINGLE register value error fix - Revert "ASoC: cs4265: SOC_SINGLE register value error fix" - Revert "net: pskb_trim_rcsum() and CHECKSUM_COMPLETE are friends" - Revert "Revert "net: pskb_trim_rcsum() and CHECKSUM_COMPLETE are friends"" Patches dropped after rebase: - net: Add non-mainline source for rtl8192cu wlan - net: Fix rtl8192cu build errors on other platforms - brcm: adds support for BCM43341 wifi - brcmfmac: Mute expected startup 'errors' - ARM64: Fix build break for RTL8187/RTL8192CU wifi - ARM64: Enable RTL8187/RTL8192CU wifi in build config - This is the driver for Sony CXD2880 DVB-T2/T tuner + demodulator - brcmfmac: add CLM download support - brcmfmac: request_firmware_direct is quieter - Sets the BCDC priority to constant 0 - brcmfmac: Disable ARP offloading when promiscuous - brcmfmac: Avoid possible out-of-bounds read - brcmfmac: Delete redundant length check - net: rtl8192cu: Normalize indentation - net: rtl8192cu: Fix implicit fallthrough warnings - Revert "Sets the BCDC priority to constant 0" - media: cxd2880: Bump to match 4.18.y version - media: cxd2880-spi: Bump to match 4.18.y version - Revert "mm: alloc_contig: re-allow CMA to compact FS pages" - Revert "Revert "mm: alloc_contig: re-allow CMA to compact FS pages"" - cxd2880: CXD2880_SPI_DRV should select DVB_CXD2880 with MEDIA_SUBDRV_AUTOSELECT - 950-0421-HID-hid-bigbenff-driver-for-BigBen-Interactive-PS3OF.patch - 950-0453-Add-hid-bigbenff-to-list-of-have_special_driver-for-.patch Make I2C built-in instead of modular as in upstream defconfig; also the easiest way to get MFD_ARIZONA enabled, which is required by kmod-sound-soc-rpi-cirrus. Add missing compatible strings from 4.9/960-add-rasbperrypi-compatible.patch, using upstream names for compute modules. Add extra patch to enable the LEDs on lan78xx. Compile-tested: bcm2708, bcm2709, bcm2710 (with CONFIG_ALL_KMODS=y) Runtime-tested: bcm2708, bcm2710 Signed-off-by: Stijn Tintel <stijn@linux-ipv6.be>
6 years ago
From 84ad00eb76af34f8a6c6941dc6da80a3f735b207 Mon Sep 17 00:00:00 2001
From: wm4 <wm4@nowhere>
Date: Wed, 13 Jan 2016 19:44:47 +0100
Subject: [PATCH 410/454] bcm2835: interpolate audio delay
It appears the GPU only sends us a message all 10ms to update
the playback progress. Other than this, the playback position
(what SNDRV_PCM_IOCTL_DELAY will return) is not updated at all.
Userspace will see jitter up to 10ms in the audio position.
Make this a bit nicer for userspace by interpolating the
position using the CPU clock.
I'm not sure if setting snd_pcm_runtime.delay is the right
approach for this. Or if there is maybe an already existing
mechanism for position interpolation in the ALSA core.
I only set SNDRV_PCM_INFO_BATCH because this appears to remove
at least one situation snd_pcm_runtime.delay is used, so I have
to worry less in which place I have to update this field, or
how it interacts with the rest of ALSA.
In the future, it might be nice to use VC_AUDIO_MSG_TYPE_LATENCY.
One problem is that it requires sending a videocore message, and
waiting for a reply, which could make the implementation much
harder due to locking and synchronization requirements.
---
.../vc04_services/bcm2835-audio/bcm2835-pcm.c | 13 +++++++++++--
.../staging/vc04_services/bcm2835-audio/bcm2835.h | 1 +
2 files changed, 12 insertions(+), 2 deletions(-)
--- a/drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c
+++ b/drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c
@@ -22,7 +22,7 @@
/* hardware definition */
static const struct snd_pcm_hardware snd_bcm2835_playback_hw = {
.info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_BLOCK_TRANSFER |
- SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID),
+ SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_BATCH),
.formats = SNDRV_PCM_FMTBIT_U8 | SNDRV_PCM_FMTBIT_S16_LE,
.rates = SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_48000,
.rate_min = 8000,
@@ -93,6 +93,8 @@ void bcm2835_playback_fifo(struct bcm283
alsa_stream->pos %= alsa_stream->buffer_size;
}
+ alsa_stream->interpolate_start = ktime_get_ns();
+
if (alsa_stream->substream) {
if (new_period)
snd_pcm_period_elapsed(alsa_stream->substream);
@@ -323,6 +325,7 @@ static int snd_bcm2835_pcm_prepare(struc
alsa_stream->buffer_size = snd_pcm_lib_buffer_bytes(substream);
alsa_stream->period_size = snd_pcm_lib_period_bytes(substream);
alsa_stream->pos = 0;
+ alsa_stream->interpolate_start = ktime_get_ns();
audio_debug("buffer_size=%d, period_size=%d pos=%d frame_bits=%d\n",
alsa_stream->buffer_size, alsa_stream->period_size,
@@ -415,13 +418,19 @@ snd_bcm2835_pcm_pointer(struct snd_pcm_s
{
struct snd_pcm_runtime *runtime = substream->runtime;
struct bcm2835_alsa_stream *alsa_stream = runtime->private_data;
-
+ u64 now = ktime_get_ns();
audio_debug("pcm_pointer... (%d) hwptr=%d appl=%d pos=%d\n", 0,
frames_to_bytes(runtime, runtime->status->hw_ptr),
frames_to_bytes(runtime, runtime->control->appl_ptr),
alsa_stream->pos);
+ /* Give userspace better delay reporting by interpolating between GPU
+ * notifications, assuming audio speed is close enough to the clock
+ * used for ktime */
+ if (alsa_stream->interpolate_start && alsa_stream->interpolate_start < now)
+ runtime->delay = -(int)div_u64((now - alsa_stream->interpolate_start) * runtime->rate, 1000000000);
+
return snd_pcm_indirect_playback_pointer(substream,
&alsa_stream->pcm_indirect,
alsa_stream->pos);
--- a/drivers/staging/vc04_services/bcm2835-audio/bcm2835.h
+++ b/drivers/staging/vc04_services/bcm2835-audio/bcm2835.h
@@ -137,6 +137,7 @@ struct bcm2835_alsa_stream {
unsigned int pos;
unsigned int buffer_size;
unsigned int period_size;
+ u64 interpolate_start;
atomic_t retrieved;
struct bcm2835_audio_instance *instance;