FAILED: patch "[PATCH] ALSA: hda/ext: preserve PPLCCTL bits when clearing reset" failed to apply to 5.15-stable tree

The patch below does not apply to the 5.15-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-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 36aa66de481d29edd63cbad9b5c4dc18c340fdf6
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026090344-refresh-reissue-e253@gregkh' --subject-prefix 'PATCH 5.15.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

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

From 36aa66de481d29edd63cbad9b5c4dc18c340fdf6 Mon Sep 17 00:00:00 2001
From: Xu Rao <[email protected]>
Date: Thu, 13 Aug 2026 14:55:24 +0800
Subject: [PATCH] ALSA: hda/ext: preserve PPLCCTL bits when clearing reset

snd_hdac_ext_stream_reset() polls PPLCCTL for STRST by masking the register value with AZX_PPLCCTL_STRST:

	val = readl(...) & AZX_PPLCCTL_STRST;

The same masked value is then used when clearing STRST. Since val contains no bits other than STRST, clearing STRST from it always produces zero. The subsequent writel() therefore writes zero to the entire PPLCCTL register instead of clearing only the reset bit.

PPLCCTL contains other stream control fields, including the stream tag in AZX_PPLCCTL_STRM_MASK. Those fields must not be modified as a side effect of clearing stream reset.

Use snd_hdac_updatel() to clear STRST, matching the existing set-reset path and preserving all unrelated PPLCCTL bits.

index 4c7506d49f55..517bd151fcc3 100644
@@ -210,8 +210,8 @@ void snd_hdac_ext_stream_reset(struct hdac_ext_stream *hext_stream)
 			break;
 		udelay(3);
 	} while (--timeout);
-	val &= ~AZX_PPLCCTL_STRST;
-	writel(val, hext_stream->pplc_addr + AZX_REG_PPLCCTL);
+	snd_hdac_updatel(hext_stream->pplc_addr, AZX_REG_PPLCCTL,
+			 AZX_PPLCCTL_STRST, 0);
 	udelay(3);
 
 	timeout = 50;

From: Len Baker <[email protected]>

[ Upstream commit f02f2f1bf9d154148325eb60d74bdf199022ea52 ]

As noted in the "Deprecated Interfaces, Language Features, Attributes, and Conventions" documentation [1], size calculations (especially multiplication) should not be performed in memory allocator (or similar) function arguments due to the risk of them overflowing. This could lead to values wrapping around and a smaller allocation being made than the caller was expecting. Using those allocations could lead to linear overflows of heap memory and other misbehaviors.

In this case this is not actually dynamic size: all the operands involved in the calculation are constant values. However it is better to refactor this anyway, just to keep the open-coded math idiom out of code.

So, use the struct_size() helper to do the arithmetic instead of the argument "size + size * count" in the kzalloc() function.

Also, take the opportunity to refactor the declaration variables to make it more easy to read.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments

Stable-dep-of: 36aa66de481d ("ALSA: hda/ext: preserve PPLCCTL bits when clearing reset")

---
 sound/usb/usx2y/usbusx2yaudio.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

index a6ed4f0230b7f..3816d2d6723da 100644
@@ -641,14 +641,15 @@ static void i_usx2y_04int(struct urb *urb)
 
 static int usx2y_rate_set(struct usx2ydev *usx2y, int rate)
 {
-	int			err = 0, i;
-	struct snd_usx2y_urb_seq	*us = NULL;
-	int			*usbdata = NULL;
-	const struct s_c2	*ra = rate == 48000 ? setrate_48000 : setrate_44100;
+	int err = 0, i;
+	struct snd_usx2y_urb_seq *us = NULL;
+	int *usbdata = NULL;
+	const struct s_c2 *ra = rate == 48000 ? setrate_48000 : setrate_44100;
 	struct urb *urb;
 
 	if (usx2y->rate != rate) {
-		us = kzalloc(sizeof(*us) + sizeof(struct urb *) * NOOF_SETRATE_URBS, GFP_KERNEL);
+		us = kzalloc(struct_size(us, urb, NOOF_SETRATE_URBS),
+			     GFP_KERNEL);
 		if (!us) {
 			err = -ENOMEM;
 			goto cleanup;

2.53.0

From: Pierre-Louis Bossart <[email protected]>

[ Upstream commit 0f7e5ee62f4c24ca9db58351c86653cc3ee0bd0e ]

The existing code maximizes confusion by using 'stream' and 'hstream' variables of different types. Examples:

struct hdac_stream *stream;
struct hdac_ext_stream *stream;
struct hdac_stream *hstream;
struct hdac_ext_stream *hstream;

with some additional copy/paste remains:
struct hdac_ext_stream *azx_dev;

This patch suggests a consistent naming across all 'hdac_ext_stream' functions. The convention is:

struct hdac_stream *hstream;
struct hdac_ext_stream *hext_stream;

No functionality change - just renaming of variables and more consistent indentation.

Stable-dep-of: 36aa66de481d ("ALSA: hda/ext: preserve PPLCCTL bits when clearing reset")

---
 include/sound/hdaudio_ext.h     |  26 ++---
 sound/hda/ext/hdac_ext_stream.c | 199 ++++++++++++++++----------------
 2 files changed, 113 insertions(+), 112 deletions(-)

index 56ea5cde5e63a..77123c3e4095b 100644
@@ -78,35 +78,35 @@ struct hdac_ext_stream {
 	container_of(s, struct hdac_ext_stream, hstream)
 
 void snd_hdac_ext_stream_init(struct hdac_bus *bus,
-				struct hdac_ext_stream *stream, int idx,
-				int direction, int tag);
+			      struct hdac_ext_stream *hext_stream, int idx,
+			      int direction, int tag);
 int snd_hdac_ext_stream_init_all(struct hdac_bus *bus, int start_idx,
-		int num_stream, int dir);
+				 int num_stream, int dir);
 void snd_hdac_stream_free_all(struct hdac_bus *bus);
 void snd_hdac_link_free_all(struct hdac_bus *bus);
 struct hdac_ext_stream *snd_hdac_ext_stream_assign(struct hdac_bus *bus,
 					   struct snd_pcm_substream *substream,
 					   int type);
-void snd_hdac_ext_stream_release(struct hdac_ext_stream *azx_dev, int type);
+void snd_hdac_ext_stream_release(struct hdac_ext_stream *hext_stream, int type);
 void snd_hdac_ext_stream_decouple_locked(struct hdac_bus *bus,
-				  struct hdac_ext_stream *azx_dev, bool decouple);
+					 struct hdac_ext_stream *hext_stream, bool decouple);
 void snd_hdac_ext_stream_decouple(struct hdac_bus *bus,
 				struct hdac_ext_stream *azx_dev, bool decouple);
 
 int snd_hdac_ext_stream_set_spib(struct hdac_bus *bus,
-				 struct hdac_ext_stream *stream, u32 value);
+				 struct hdac_ext_stream *hext_stream, u32 value);
 int snd_hdac_ext_stream_get_spbmaxfifo(struct hdac_bus *bus,
-				 struct hdac_ext_stream *stream);
+				       struct hdac_ext_stream *hext_stream);
 void snd_hdac_ext_stream_drsm_enable(struct hdac_bus *bus,
 				bool enable, int index);
 int snd_hdac_ext_stream_set_dpibr(struct hdac_bus *bus,
-				struct hdac_ext_stream *stream, u32 value);
-int snd_hdac_ext_stream_set_lpib(struct hdac_ext_stream *stream, u32 value);
+				struct hdac_ext_stream *hext_stream, u32 value);
+int snd_hdac_ext_stream_set_lpib(struct hdac_ext_stream *hext_stream, u32 value);
 
-void snd_hdac_ext_link_stream_start(struct hdac_ext_stream *hstream);
-void snd_hdac_ext_link_stream_clear(struct hdac_ext_stream *hstream);
-void snd_hdac_ext_link_stream_reset(struct hdac_ext_stream *hstream);
-int snd_hdac_ext_link_stream_setup(struct hdac_ext_stream *stream, int fmt);
+void snd_hdac_ext_link_stream_start(struct hdac_ext_stream *hext_stream);
+void snd_hdac_ext_link_stream_clear(struct hdac_ext_stream *hext_stream);
+void snd_hdac_ext_link_stream_reset(struct hdac_ext_stream *hext_stream);
+int snd_hdac_ext_link_stream_setup(struct hdac_ext_stream *hext_stream, int fmt);
 
 struct hdac_ext_link {
 	struct hdac_bus *bus;

2.53.0

From: Xu Rao <[email protected]>

[ Upstream commit 36aa66de481d29edd63cbad9b5c4dc18c340fdf6 ]

snd_hdac_ext_stream_reset() polls PPLCCTL for STRST by masking the register value with AZX_PPLCCTL_STRST:

	val = readl(...) & AZX_PPLCCTL_STRST;

The same masked value is then used when clearing STRST. Since val contains no bits other than STRST, clearing STRST from it always produces zero. The subsequent writel() therefore writes zero to the entire PPLCCTL register instead of clearing only the reset bit.

PPLCCTL contains other stream control fields, including the stream tag in AZX_PPLCCTL_STRM_MASK. Those fields must not be modified as a side effect of clearing stream reset.

Use snd_hdac_updatel() to clear STRST, matching the existing set-reset path and preserving all unrelated PPLCCTL bits.

---
 sound/hda/ext/hdac_ext_stream.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

index d2b5724b463ff..ae9228d52da0e 100644
@@ -183,8 +183,8 @@ void snd_hdac_ext_link_stream_reset(struct hdac_ext_stream *hext_stream)
 			break;
 		udelay(3);
 	} while (--timeout);
-	val &= ~AZX_PPLCCTL_STRST;
-	writel(val, hext_stream->pplc_addr + AZX_REG_PPLCCTL);
+	snd_hdac_updatel(hext_stream->pplc_addr, AZX_REG_PPLCCTL,
+			 AZX_PPLCCTL_STRST, 0);
 	udelay(3);
 
 	timeout = 50;

2.53.0