Workaround broken sound issue by disabling SG-buffer

Since about 5.17 kernel (2c95b92ecd92e784785b1db8cccc4f0f2bfa850c
upstream commit specifically), audio stops working after some time. The
real solution isn't known yet, but as a workaround disable problematic
feature (SG-buffer) for now. See linked issue and upstream discussion at
[1] for details.

Fixes QubesOS/qubes-issues#7465
[1] https://lore.kernel.org/alsa-devel/Y6E9VixS7sV0kpWQ@mail-itl/T/

Author: marmarek

0001-sound-Disable-SG-buffer.patch

@@ -0,0 +1,30 @@
+From bcc68c3829df041bf22ee493f8eb58fce230303b Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Marek=20Marczykowski-G=C3=B3recki?=
+ <marmarek@invisiblethingslab.com>
+Date: Tue, 27 Dec 2022 15:49:46 +0100
+Subject: [PATCH] sound: Disable SG-buffer
+
+This appears to be broken under Xen PV (or other Qubes-specific
+factor?), so disable it until fixed.
+---
+ sound/core/Kconfig | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/sound/core/Kconfig b/sound/core/Kconfig
+index 12990d9a4dff..18798d99021d 100644
+--- a/sound/core/Kconfig
++++ b/sound/core/Kconfig
+@@ -225,8 +225,8 @@ config SND_VMASTER
+ 	bool
+ 
+ config SND_DMA_SGBUF
+-	def_bool y
+-	depends on X86
++	def_bool n
++#	depends on X86
+ 
+ config SND_CTL_LED
+ 	tristate
+-- 
+2.37.3
+

kernel.spec.in

@@ -146,6 +146,7 @@ Patch12: 0013-xen-pcifront-pciback-Update-pciif.h-with-err-and-res.patch
 Patch16: 0001-usbip-tweak-clear-halt-with-simple-reset.patch
 Patch19: increase-reclaim-speed.patch
 Patch25: 0001-Re-enable-interrupts-before-loading-PNVM.patch
+Patch26: 0001-sound-Disable-SG-buffer.patch
 
 %description
 Qubes Dom0 kernel.