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 6a5b387..11718b4 100644 (file)
--- a/sound/pci/intel8x0.c
+++ b/sound/pci/intel8x0.c
@@ -32,7 +32,7 @@
 #include <linux/init.h>
 #include <linux/pci.h>
 #include <linux/slab.h>
-#include <linux/moduleparam.h>
+#include <linux/module.h>
 #include <sound/core.h>
 #include <sound/pcm.h>
 #include <sound/ac97_codec.h>
@@ -42,6 +42,12 @@
 #include <asm/pgtable.h>
 #include <asm/cacheflush.h>
 
+#ifdef CONFIG_KVM_GUEST
+#include <linux/kvm_para.h>
+#else
+#define kvm_para_available() (0)
+#endif
+
 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
 MODULE_DESCRIPTION("Intel 82801AA,82901AB,i810,i820,i830,i840,i845,MX440; SiS 7012; Ali 5455");
 MODULE_LICENSE("GPL");
@@ -77,6 +83,7 @@ static int buggy_semaphore;
 static int buggy_irq = -1; /* auto-check */
 static int xbox;
 static int spdif_aclink = -1;
+static int inside_vm = -1;
 
 module_param(index, int, 0444);
 MODULE_PARM_DESC(index, "Index value for Intel i8x0 soundcard.");
@@ -94,6 +101,8 @@ module_param(xbox, bool, 0444);
 MODULE_PARM_DESC(xbox, "Set to 1 for Xbox, if you have problems with the AC'97 codec detection.");
 module_param(spdif_aclink, int, 0444);
 MODULE_PARM_DESC(spdif_aclink, "S/PDIF over AC-link.");
+module_param(inside_vm, bool, 0444);
+MODULE_PARM_DESC(inside_vm, "KVM/Parallels optimization.");
 
 /* just for backward compatibility */
 static int enable;
@@ -400,6 +409,7 @@ struct intel8x0 {
        unsigned buggy_irq: 1;          /* workaround for buggy mobos */
        unsigned xbox: 1;               /* workaround for Xbox AC'97 detection */
        unsigned buggy_semaphore: 1;    /* workaround for buggy codec semaphore */
+       unsigned inside_vm: 1;          /* enable VM optimization */
 
        int spdif_idx;  /* SPDIF BAR index; *_SPBAR or -1 if use PCMOUT */
        unsigned int sdm_saved; /* SDM reg value */
@@ -1065,8 +1075,18 @@ static snd_pcm_uframes_t snd_intel8x0_pcm_pointer(struct snd_pcm_substream *subs
                        udelay(10);
                        continue;
                }
-               if (civ == igetbyte(chip, ichdev->reg_offset + ICH_REG_OFF_CIV) &&
-                   ptr1 == igetword(chip, ichdev->reg_offset + ichdev->roff_picb))
+               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))
                        break;
        } while (timeout--);
        ptr = ichdev->last_pos;
@@ -2917,6 +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,
@@ -2984,6 +3043,8 @@ static int __devinit snd_intel8x0_create(struct snd_card *card,
        if (xbox)
                chip->xbox = 1;
 
+       chip->inside_vm = snd_intel8x0_inside_vm(pci);
+
        if (pci->vendor == PCI_VENDOR_ID_INTEL &&
            pci->device == PCI_DEVICE_ID_INTEL_440MX)
                chip->fix_nocache = 1; /* enable workaround */