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FAILED: patch "[PATCH] ASoC: tegra: Fix redundant PLLA and PLLA_OUT0 updates" failed to apply to 6.1-stable tree

PATCH [email protected] 1 participant 1 message Oct 4, 2023

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Stable branch Sound ASoC Tegra architecture support
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The patch below does not apply to the 6.1-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x e765886249c533e1bb5cbc3cd741bad677417312
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2023100451-matchless-aching-f16c@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From e765886249c533e1bb5cbc3cd741bad677417312 Mon Sep 17 00:00:00 2001
From: Sameer Pujar <[email protected]>
Date: Thu, 7 Sep 2023 20:32:25 +0530
Subject: [PATCH] ASoC: tegra: Fix redundant PLLA and PLLA_OUT0 updates

Tegra audio graph card has many DAI links which connects internal AHUB modules and external audio codecs. Since these are DPCM links, hw_params() call in the machine driver happens for each connected BE link and PLLA is updated every time. This is not really needed for all links as only I/O link DAIs derive respective clocks from PLLA_OUT0 and thus from PLLA. Hence add checks to limit the clock updates to DAIs over I/O links.

This found to be fixing a DMIC clock discrepancy which is suspected to happen because of back to back quick PLLA and PLLA_OUT0 rate updates. This was observed on Jetson TX2 platform where DMIC clock ended up with unexpected value.

Fixes 202e2f774543 ("ASoC: tegra: Add audio graph based card driver")
Cc [email protected]
Signed-off-by Sameer Pujar <[email protected]>
Link https://lore.kernel.org/r/[email protected] open here
Signed-off-by Mark Brown <[email protected]>
sound/soc/tegra/tegra_audio_graph_card.c +17 -13
index 1f2c5018bf5a..4737e776d383 100644
@@ -10,6 +10,7 @@
 #include <linux/platform_device.h>
 #include <sound/graph_card.h>
 #include <sound/pcm_params.h>
+#include <sound/soc-dai.h>
 
 #define MAX_PLLA_OUT0_DIV 128
 

@@ -44,6 +45,21 @@ struct tegra_audio_cdata {
 	unsigned int plla_out0_rates[NUM_RATE_TYPE];
 };
 
+static bool need_clk_update(struct snd_soc_dai *dai)
+{
+	if (snd_soc_dai_is_dummy(dai) ||
+	    !dai->driver->ops ||
+	    !dai->driver->name)
+		return false;
+
+	if (strstr(dai->driver->name, "I2S") ||
+	    strstr(dai->driver->name, "DMIC") ||
+	    strstr(dai->driver->name, "DSPK"))
+		return true;
+
+	return false;
+}
+
 /* Setup PLL clock as per the given sample rate */
 static int tegra_audio_graph_update_pll(struct snd_pcm_substream *substream,
 					struct snd_pcm_hw_params *params)

@@ -140,19 +156,7 @@ static int tegra_audio_graph_hw_params(struct snd_pcm_substream *substream,
 	struct snd_soc_dai *cpu_dai = asoc_rtd_to_cpu(rtd, 0);
 	int err;
 
-	/*
-	 * This gets called for each DAI link (FE or BE) when DPCM is used.
-	 * We may not want to update PLLA rate for each call. So PLLA update
-	 * must be restricted to external I/O links (I2S, DMIC or DSPK) since
-	 * they actually depend on it. I/O modules update their clocks in
-	 * hw_param() of their respective component driver and PLLA rate
-	 * update here helps them to derive appropriate rates.
-	 *
-	 * TODO: When more HW accelerators get added (like sample rate
-	 * converter, volume gain controller etc., which don't really
-	 * depend on PLLA) we need a better way to filter here.
-	 */
-	if (cpu_dai->driver->ops && rtd->dai_link->no_pcm) {
+	if (need_clk_update(cpu_dai)) {
 		err = tegra_audio_graph_update_pll(substream, params);
 		if (err)
 			return err;