Merge branch 'for-linus' of git://oss.sgi.com/xfs/xfs

[pandora-kernel.git] / sound / pci / intel8x0.c

diff --git a/sound/pci/intel8x0.c b/sound/pci/intel8x0.c
index 29e3125..11718b4 100644 (file)
--- a/sound/pci/intel8x0.c
+++ b/sound/pci/intel8x0.c
@@ -1077,6 +1077,13 @@ static snd_pcm_uframes_t snd_intel8x0_pcm_pointer(struct snd_pcm_substream *subs
                }
                if (civ != igetbyte(chip, ichdev->reg_offset + ICH_REG_OFF_CIV))
                        continue;
+
+               /* IO read operation is very expensive inside virtual machine
+                * as it is emulated. The probability that subsequent PICB read
+                * will return different result is high enough to loop till
+                * timeout here.
+                * Same CIV is strict enough condition to be sure that PICB
+                * is valid inside VM on emulated card. */
                if (chip->inside_vm)
                        break;
                if (ptr1 == igetword(chip, ichdev->reg_offset + ichdev->roff_picb))
@@ -2930,6 +2937,45 @@ static unsigned int sis_codec_bits[3] = {
        ICH_PCR, ICH_SCR, ICH_SIS_TCR
 };
 
+static int __devinit snd_intel8x0_inside_vm(struct pci_dev *pci)
+{
+       int result  = inside_vm;
+       char *msg   = NULL;
+
+       /* check module parameter first (override detection) */
+       if (result >= 0) {
+               msg = result ? "enable (forced) VM" : "disable (forced) VM";
+               goto fini;
+       }
+
+       /* detect KVM and Parallels virtual environments */
+       result = kvm_para_available();
+#ifdef X86_FEATURE_HYPERVISOR
+       result = result || boot_cpu_has(X86_FEATURE_HYPERVISOR);
+#endif
+       if (!result)
+               goto fini;
+
+       /* check for known (emulated) devices */
+       if (pci->subsystem_vendor == 0x1af4 &&
+           pci->subsystem_device == 0x1100) {
+               /* KVM emulated sound, PCI SSID: 1af4:1100 */
+               msg = "enable KVM";
+       } else if (pci->subsystem_vendor == 0x1ab8) {
+               /* Parallels VM emulated sound, PCI SSID: 1ab8:xxxx */
+               msg = "enable Parallels VM";
+       } else {
+               msg = "disable (unknown or VT-d) VM";
+               result = 0;
+       }
+
+fini:
+       if (msg != NULL)
+               printk(KERN_INFO "intel8x0: %s optimization\n", msg);
+
+       return result;
+}
+
 static int __devinit snd_intel8x0_create(struct snd_card *card,
                                         struct pci_dev *pci,
                                         unsigned long device_type,
@@ -2997,9 +3043,7 @@ static int __devinit snd_intel8x0_create(struct snd_card *card,
        if (xbox)
                chip->xbox = 1;
 
-       chip->inside_vm = inside_vm;
-       if (inside_vm)
-               printk(KERN_INFO "intel8x0: enable KVM optimization\n");
+       chip->inside_vm = snd_intel8x0_inside_vm(pci);
 
        if (pci->vendor == PCI_VENDOR_ID_INTEL &&
            pci->device == PCI_DEVICE_ID_INTEL_440MX)
@@ -3243,14 +3287,6 @@ static int __devinit snd_intel8x0_probe(struct pci_dev *pci,
                        buggy_irq = 0;
        }
 
-       if (inside_vm < 0) {
-               /* detect KVM and Parallels virtual environments */
-               inside_vm = kvm_para_available();
-#if defined(__i386__) || defined(__x86_64__)
-               inside_vm = inside_vm || boot_cpu_has(X86_FEATURE_HYPERVISOR);
-#endif
-       }
-
        if ((err = snd_intel8x0_create(card, pci, pci_id->driver_data,
                                       &chip)) < 0) {
                snd_card_free(card);