Revert "ALSA: hda: Conditionally use snooping for AMD HDMI"

BugLink: https://bugs.launchpad.net/bugs/2089884

commit 3f7f36a upstream.

This reverts commit 478689b.

The fix seems leading to regressions for other systems.
Also, the way to check the presence of IOMMU via get_dma_ops() isn't
reliable and it's no longer applicable for 6.12.  After all, it's no
right fix, so let's revert it at first.

To be noted, the PCM buffer allocation has been changed to try the
continuous pages at first since 6.12, so the problem could be already
addressed without this hackish workaround.

Reported-by: Salvatore Bonaccorso <[email protected]>
Closes: https://lore.kernel.org/[email protected]
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Takashi Iwai <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Koichiro Den <[email protected]>
Signed-off-by: Roxana Nicolescu <[email protected]>

Author: tiwai

sound/pci/hda/hda_controller.h

@@ -28,7 +28,7 @@
 #else
 #define AZX_DCAPS_I915_COMPONENT 0		/* NOP */
 #endif
-#define AZX_DCAPS_AMD_ALLOC_FIX	(1 << 14)	/* AMD allocation workaround */
+/* 14 unused */
 #define AZX_DCAPS_CTX_WORKAROUND (1 << 15)	/* X-Fi workaround */
 #define AZX_DCAPS_POSFIX_LPIB	(1 << 16)	/* Use LPIB as default */
 #define AZX_DCAPS_AMD_WORKAROUND (1 << 17)	/* AMD-specific workaround */

sound/pci/hda/hda_intel.c

@@ -40,7 +40,6 @@
 
 #ifdef CONFIG_X86
 /* for snoop control */
-#include <linux/dma-map-ops.h>
 #include <asm/set_memory.h>
 #include <asm/cpufeature.h>
 #endif
@@ -302,7 +301,7 @@ enum {
 
 /* quirks for ATI HDMI with snoop off */
 #define AZX_DCAPS_PRESET_ATI_HDMI_NS \
-	(AZX_DCAPS_PRESET_ATI_HDMI | AZX_DCAPS_AMD_ALLOC_FIX)
+	(AZX_DCAPS_PRESET_ATI_HDMI | AZX_DCAPS_SNOOP_OFF)
 
 /* quirks for AMD SB */
 #define AZX_DCAPS_PRESET_AMD_SB \
@@ -1710,13 +1709,6 @@ static void azx_check_snoop_available(struct azx *chip)
 	if (chip->driver_caps & AZX_DCAPS_SNOOP_OFF)
 		snoop = false;
 
-#ifdef CONFIG_X86
-	/* check the presence of DMA ops (i.e. IOMMU), disable snoop conditionally */
-	if ((chip->driver_caps & AZX_DCAPS_AMD_ALLOC_FIX) &&
-	    !get_dma_ops(chip->card->dev))
-		snoop = false;
-#endif
-
 	chip->snoop = snoop;
 	if (!snoop) {
 		dev_info(chip->card->dev, "Force to non-snoop mode\n");