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Diffstat (limited to 'target/linux/bcm27xx/patches-5.4/950-0368-Pisound-MIDI-communication-fixes-for-scaled-down-CPU.patch')
-rw-r--r--target/linux/bcm27xx/patches-5.4/950-0368-Pisound-MIDI-communication-fixes-for-scaled-down-CPU.patch100
1 files changed, 100 insertions, 0 deletions
diff --git a/target/linux/bcm27xx/patches-5.4/950-0368-Pisound-MIDI-communication-fixes-for-scaled-down-CPU.patch b/target/linux/bcm27xx/patches-5.4/950-0368-Pisound-MIDI-communication-fixes-for-scaled-down-CPU.patch
new file mode 100644
index 0000000000..0221803993
--- /dev/null
+++ b/target/linux/bcm27xx/patches-5.4/950-0368-Pisound-MIDI-communication-fixes-for-scaled-down-CPU.patch
@@ -0,0 +1,100 @@
+From 67dd4d137557909279a21c1b5de87a24c84903f9 Mon Sep 17 00:00:00 2001
+From: Giedrius <giedrius@blokas.io>
+Date: Tue, 7 Jan 2020 11:04:21 +0200
+Subject: [PATCH] Pisound: MIDI communication fixes for scaled down
+ CPU.
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+* Increased maximum SPI communication speed to avoid running too slow
+ when the CPU is scaled down and losing MIDI data.
+
+* Keep track of buffer usage in millibytes for higher precision.
+
+Signed-off-by: Giedrius Trainavičius <giedrius@blokas.io>
+---
+ sound/soc/bcm/pisound.c | 31 ++++++++++++++++++-------------
+ 1 file changed, 18 insertions(+), 13 deletions(-)
+
+--- a/sound/soc/bcm/pisound.c
++++ b/sound/soc/bcm/pisound.c
+@@ -1,6 +1,6 @@
+ /*
+ * Pisound Linux kernel module.
+- * Copyright (C) 2016-2019 Vilniaus Blokas UAB, https://blokas.io/pisound
++ * Copyright (C) 2016-2020 Vilniaus Blokas UAB, https://blokas.io/pisound
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+@@ -326,7 +326,7 @@ static void spi_transfer(const uint8_t *
+ transfer.tx_buf = txbuf;
+ transfer.rx_buf = rxbuf;
+ transfer.len = len;
+- transfer.speed_hz = 100000;
++ transfer.speed_hz = 150000;
+ transfer.delay_usecs = 10;
+ spi_message_add_tail(&transfer, &msg);
+
+@@ -403,9 +403,9 @@ static struct spi_device *pisnd_spi_find
+ static void pisnd_work_handler(struct work_struct *work)
+ {
+ enum { TRANSFER_SIZE = 4 };
+- enum { PISOUND_OUTPUT_BUFFER_SIZE = 128 };
+- enum { MIDI_BYTES_PER_SECOND = 3125 };
+- int out_buffer_used = 0;
++ enum { PISOUND_OUTPUT_BUFFER_SIZE_MILLIBYTES = 127 * 1000 };
++ enum { MIDI_MILLIBYTES_PER_JIFFIE = (3125 * 1000) / HZ };
++ int out_buffer_used_millibytes = 0;
+ unsigned long now;
+ uint8_t val;
+ uint8_t txbuf[TRANSFER_SIZE];
+@@ -445,7 +445,9 @@ static void pisnd_work_handler(struct wo
+ had_data = false;
+ memset(txbuf, 0, sizeof(txbuf));
+ for (i = 0; i < sizeof(txbuf) &&
+- out_buffer_used < PISOUND_OUTPUT_BUFFER_SIZE;
++ ((out_buffer_used_millibytes+1000 <
++ PISOUND_OUTPUT_BUFFER_SIZE_MILLIBYTES) ||
++ g_ledFlashDurationChanged);
+ i += 2) {
+
+ val = 0;
+@@ -458,7 +460,7 @@ static void pisnd_work_handler(struct wo
+ } else if (kfifo_get(&spi_fifo_out, &val)) {
+ txbuf[i+0] = 0x0f;
+ txbuf[i+1] = val;
+- ++out_buffer_used;
++ out_buffer_used_millibytes += 1000;
+ }
+ }
+
+@@ -469,12 +471,14 @@ static void pisnd_work_handler(struct wo
+ * rate.
+ */
+ now = jiffies;
+- out_buffer_used -=
+- (MIDI_BYTES_PER_SECOND / HZ) /
+- (now - last_transfer_at);
+- if (out_buffer_used < 0)
+- out_buffer_used = 0;
+- last_transfer_at = now;
++ if (now != last_transfer_at) {
++ out_buffer_used_millibytes -=
++ (now - last_transfer_at) *
++ MIDI_MILLIBYTES_PER_JIFFIE;
++ if (out_buffer_used_millibytes < 0)
++ out_buffer_used_millibytes = 0;
++ last_transfer_at = now;
++ }
+
+ for (i = 0; i < sizeof(rxbuf); i += 2) {
+ if (rxbuf[i]) {
+@@ -489,6 +493,7 @@ static void pisnd_work_handler(struct wo
+ || !kfifo_is_empty(&spi_fifo_out)
+ || pisnd_spi_has_more()
+ || g_ledFlashDurationChanged
++ || out_buffer_used_millibytes != 0
+ );
+
+ if (!kfifo_is_empty(&spi_fifo_in) && g_recvCallback)