ALSA: hda - Limit 40bit DMA for AMD HDMI controllers

commit 413cbf46 upstream.

AMD/ATI HDMI controller chip models, we already have a filter to lower
to 32bit DMA, but the rest are supposed to be working with 64bit
although the hardware doesn't really work with 63bit but only with 40
or 48bit DMA.  In this patch, we take 40bit DMA for safety for the
AMD/ATI controllers as the graphics drivers does.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[lizf: Backported to 3.4:
 - adjust context
 - s/AZX_GCAP_640K/ICH6_GCAP_64OK]
Signed-off-by: Zefan Li <lizefan@huawei.com>

sound/pci/hda/hda_intel.c

@@ -2685,6 +2685,7 @@ static int __devinit azx_create(struct snd_card *card, struct pci_dev *pci,
 	struct azx *chip;
 	int i, err;
 	unsigned short gcap;
+	unsigned int dma_bits = 64;
 	static struct snd_device_ops ops = {
 		.dev_free = azx_dev_free,
 	};
@@ -2780,9 +2781,14 @@ static int __devinit azx_create(struct snd_card *card, struct pci_dev *pci,
 	gcap = azx_readw(chip, GCAP);
 	snd_printdd(SFX "chipset global capabilities = 0x%x\n", gcap);
 
+	/* AMD devices support 40 or 48bit DMA, take the safe one */
+	if (chip->pci->vendor == PCI_VENDOR_ID_AMD)
+		dma_bits = 40;
+
 	/* disable SB600 64bit support for safety */
 	if (chip->pci->vendor == PCI_VENDOR_ID_ATI) {
 		struct pci_dev *p_smbus;
+		dma_bits = 40;
 		p_smbus = pci_get_device(PCI_VENDOR_ID_ATI,
 					 PCI_DEVICE_ID_ATI_SBX00_SMBUS,
 					 NULL);
@@ -2812,9 +2818,11 @@ static int __devinit azx_create(struct snd_card *card, struct pci_dev *pci,
 	}
 
 	/* allow 64bit DMA address if supported by H/W */
-	if ((gcap & ICH6_GCAP_64OK) && !pci_set_dma_mask(pci, DMA_BIT_MASK(64)))
-		pci_set_consistent_dma_mask(pci, DMA_BIT_MASK(64));
-	else {
+	if (!(gcap & ICH6_GCAP_64OK))
+		dma_bits = 32;
+	if (!pci_set_dma_mask(pci, DMA_BIT_MASK(dma_bits))) {
+		pci_set_consistent_dma_mask(pci, DMA_BIT_MASK(dma_bits));
+	} else {
 		pci_set_dma_mask(pci, DMA_BIT_MASK(32));
 		pci_set_consistent_dma_mask(pci, DMA_BIT_MASK(32));
 	}