path: root/x11-drivers/nvidia-drivers/files/NVIDIA_kernel-173.14.05-2419292.diff

diff -ru usr/src/nv/Makefile.kbuild usr/src/nv.2419292/Makefile.kbuild
--- usr/src/nv/Makefile.kbuild	2008-05-19 00:37:02.000000000 -0700
+++ usr/src/nv.2419292/Makefile.kbuild	2008-05-21 12:07:57.551201274 -0700
@@ -166,10 +166,6 @@
 CFLAGS += -DNV_MAP_REGISTERS_EARLY
 endif
 
-ifeq ($(shell echo $(NV_BUILD_NV_PAT_SUPPORT)),1)
-CFLAGS += -DNV_BUILD_NV_PAT_SUPPORT
-endif
-
 ifneq ($(PATCHLEVEL), 4)
  COMPILE_TESTS = \
 	remap_page_range \
diff -ru usr/src/nv/Makefile.nvidia usr/src/nv.2419292/Makefile.nvidia
--- usr/src/nv/Makefile.nvidia	2008-05-19 00:37:02.000000000 -0700
+++ usr/src/nv.2419292/Makefile.nvidia	2008-05-21 12:08:08.771840702 -0700
@@ -56,10 +56,6 @@
 CFLAGS += -DNV_MAP_REGISTERS_EARLY
 endif
 
-ifeq ($(shell echo $(NV_BUILD_NV_PAT_SUPPORT)),1)
-CFLAGS += -DNV_BUILD_NV_PAT_SUPPORT
-endif
-
 INCLUDES += -I$(KERNEL_HEADERS)
 
 COMPILE_TESTS = \
diff -ru usr/src/nv/nv-linux.h usr/src/nv.2419292/nv-linux.h
--- usr/src/nv/nv-linux.h	2008-05-19 00:37:01.000000000 -0700
+++ usr/src/nv.2419292/nv-linux.h	2008-05-21 12:07:19.741046595 -0700
@@ -145,16 +145,19 @@
 #endif
 
 #if (defined(NVCPU_X86) || defined(NVCPU_X86_64)) && !defined(CONFIG_XEN)
-#define NV_BUILD_NV_PAT_SUPPORT 1
+#define NV_ENABLE_PAT_SUPPORT
 #endif
 
-#if defined(NV_BUILD_NV_PAT_SUPPORT)
-#include "pat.h"
+#define NV_PAT_MODE_DISABLED    0
+#define NV_PAT_MODE_KERNEL      1
+#define NV_PAT_MODE_BUILTIN     2
+
+extern int nv_pat_mode;
+
 #if defined(CONFIG_HOTPLUG_CPU)
 #include <linux/cpu.h>              /* CPU hotplug support              */
 #include <linux/notifier.h>         /* struct notifier_block, etc       */
 #endif
-#endif
 
 #if (defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE))
 #include <linux/i2c.h>
@@ -681,6 +684,13 @@
 #define nv_down(lock)                   down(&lock)
 #define nv_up(lock)                     up(&lock)
 
+#define NV_INIT_MUTEX(mutex)                       \
+    {                                              \
+        struct semaphore __mutex =                 \
+            __SEMAPHORE_INITIALIZER(*(mutex), 1);  \
+        *(mutex) = __mutex;                        \
+    }
+
 #if defined (KERNEL_2_4)
 #  define NV_IS_SUSER()                 suser()
 #  define NV_PCI_DEVICE_NAME(dev)       ((dev)->name)
@@ -1029,20 +1039,6 @@
         return new_prot;
     }
 #endif
-
-#if defined(NV_BUILD_NV_PAT_SUPPORT) && !defined (pgprot_writecombined)
-static inline pgprot_t pgprot_writecombined(pgprot_t old_prot)
-    {
-        pgprot_t new_prot = old_prot;
-        if (boot_cpu_data.x86 > 3)
-        {
-            pgprot_val(old_prot) &= ~(_PAGE_PCD | _PAGE_PWT);
-            new_prot = __pgprot(pgprot_val(old_prot) | _PAGE_WRTCOMB);
-        }
-        return new_prot;
-    }
-#endif
-
 #endif /* defined(NVCPU_X86) || defined(NVCPU_X86_64) */
 
 #if defined(KERNEL_2_4) && defined(NVCPU_X86) && !defined(pfn_to_page)
@@ -1142,8 +1138,6 @@
     struct semaphore at_lock;
 } nv_linux_state_t;
 
-extern int nv_pat_enabled;
-
 #if defined(NV_LINUX_ACPI_EVENTS_SUPPORTED)
 /*
  * acpi data storage structure
diff -ru usr/src/nv/nv-reg.h usr/src/nv.2419292/nv-reg.h
--- usr/src/nv/nv-reg.h	2008-05-19 00:37:01.000000000 -0700
+++ usr/src/nv.2419292/nv-reg.h	2008-05-21 12:07:23.313250167 -0700
@@ -471,6 +471,37 @@
 #define __NV_RM_EDGE_INTR_CHECK  RMEdgeIntrCheck
 #define NV_REG_RM_EDGE_INTR_CHECK NV_REG_STRING(__NV_RM_EDGE_INTR_CHECK)
 
+/*
+ * Option: UsePageAttributeTable
+ *
+ * Description:
+ *
+ * Enable/disable use of the page attribute table (PAT) available in
+ * modern x86/x86-64 processors to set the effective memory type of memory
+ * mappings to write-combining (WC). If disabled, the driver will fall
+ * back to using MTRRs, if possible.
+ *
+ * If enabled, an x86 processor with PAT support is present and the host
+ * system's Linux kernel did not configure one of the PAT entries to
+ * indicate the WC memory type, the driver will change the second entry in
+ * the PAT from its default (write-through (WT)) to WC at module load
+ * time. If the kernel did update one of the PAT entries, the driver will
+ * not modify the PAT.
+ *
+ * In both cases, the driver will honor attempts to map memory with the WC
+ * memory type by selecting the appropriate PAT entry using the correct
+ * set of PTE flags.
+ *
+ * Possible values:
+ *
+ * ~0 = use the NVIDIA driver's default logic (default)
+ *  1 = enable use of the PAT for WC mappings.
+ *  0 = disable use of the PAT for WC mappings.
+ */
+
+#define __NV_USE_PAGE_ATTRIBUTE_TABLE UsePageAttributeTable
+#define NV_USE_PAGE_ATTRIBUTE_TABLE NV_REG_STRING(__NV_USE_PAGE_ATTRIBUTE_TABLE)
+
 
 
 #if defined(NV_DEFINE_REGISTRY_KEY_TABLE)
@@ -495,6 +526,7 @@
 NV_DEFINE_REG_ENTRY(__NV_UPDATE_MEMORY_TYPES, ~0);
 NV_DEFINE_REG_ENTRY(__NV_USE_VBIOS, 1);
 NV_DEFINE_REG_ENTRY(__NV_RM_EDGE_INTR_CHECK, 1);
+NV_DEFINE_REG_ENTRY(__NV_USE_PAGE_ATTRIBUTE_TABLE, ~0);
 
 #if defined(NV_LINUX)
 NV_DEFINE_REG_STRING_ENTRY(__NV_REGISTRY_DWORDS, NULL);
@@ -540,6 +572,7 @@
     NV_DEFINE_PARAMS_TABLE_ENTRY(__NV_UPDATE_MEMORY_TYPES),
     NV_DEFINE_PARAMS_TABLE_ENTRY(__NV_USE_VBIOS),
     NV_DEFINE_PARAMS_TABLE_ENTRY(__NV_RM_EDGE_INTR_CHECK),
+    NV_DEFINE_PARAMS_TABLE_ENTRY(__NV_USE_PAGE_ATTRIBUTE_TABLE),
     {NULL, NULL, NULL}
 };
 
diff -ru usr/src/nv/nv.c usr/src/nv.2419292/nv.c
--- usr/src/nv/nv.c	2008-05-19 00:37:01.000000000 -0700
+++ usr/src/nv.2419292/nv.c	2008-05-21 12:07:28.313535114 -0700
@@ -22,10 +22,9 @@
 #endif
 
 #if defined(KERNEL_2_4) && (defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE))
-// weak linking?
 extern int i2c_add_adapter (struct i2c_adapter *) __attribute__ ((weak));
 extern int i2c_del_adapter (struct i2c_adapter *) __attribute__ ((weak));
-#endif // defined(KERNEL_2_4) && (defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE))
+#endif
 
 /*
  * our global state; one per device
@@ -41,14 +40,7 @@
 static struct pm_dev *apm_nv_dev[NV_MAX_DEVICES] = { 0 };
 #endif
 
-int nv_pat_enabled = 0;
-
-#if !defined(NV_BUILD_NV_PAT_SUPPORT)
-static int nv_disable_pat = 1;
-#else
-static int nv_disable_pat = 0;
-NV_MODULE_PARAMETER(nv_disable_pat);
-#endif
+int nv_pat_mode = NV_PAT_MODE_DISABLED;
 
 #if defined(NVCPU_X86) || defined(NVCPU_X86_64)
 NvU64 __nv_supported_pte_mask = ~_PAGE_NX;
@@ -611,7 +603,7 @@
     nv_state_t *nv;
     nv_linux_state_t *nvl;
 
-    proc_nvidia = create_proc_entry("nvidia", d_flags, proc_root_driver);
+    proc_nvidia = create_proc_entry("driver/nvidia", d_flags, NULL);
     if (!proc_nvidia)
         goto failed;
 
@@ -863,18 +855,20 @@
 static int   __nv_enable_pat_support   (void);
 static void  __nv_disable_pat_support  (void);
 
-#if defined(NV_BUILD_NV_PAT_SUPPORT)
+#if defined(NV_ENABLE_PAT_SUPPORT)
 /*
- * Private PAT support for use by the NVIDIA driver. This is an
- * interim solution until the kernel offers PAT support.
+ * Private PAT support for use by the NVIDIA driver. This is used on
+ * kernels that do not modify the PAT to include a write-combining
+ * entry.
  */
-static int   __check_pat_support       (void);
+static int   __determine_pat_mode      (void);
 static void  __nv_setup_pat_entries    (void *);
 static void  __nv_restore_pat_entries  (void *);
 
-#define NV_READ_PAT_ENTRIES(pat1, pat2)   rdmsr(IA32_CR_PAT, (pat1), (pat2))
-#define NV_WRITE_PAT_ENTRIES(pat1, pat2)  wrmsr(IA32_CR_PAT, (pat1), (pat2))
-#define NV_PAT_ENTRY(pat, index)          (((pat) & (0xff<<((index)*8)))>>((index)*8))
+#define NV_READ_PAT_ENTRIES(pat1, pat2)   rdmsr(0x277, (pat1), (pat2))
+#define NV_WRITE_PAT_ENTRIES(pat1, pat2)  wrmsr(0x277, (pat1), (pat2))
+#define NV_PAT_ENTRY(pat, index) \
+    (((pat) & (0xff << ((index)*8))) >> ((index)*8))
 
 static inline void __nv_disable_caches(unsigned long *cr4)
 {
@@ -895,39 +889,47 @@
     if (cr4 & 0x80) write_cr4(cr4);
 }
 
-static int __check_pat_support()
+static int __determine_pat_mode()
 {
     unsigned int pat1, pat2, i;
+    U008 PAT_WC_index;
 
-    if (!test_bit(X86_FEATURE_PAT, (volatile unsigned long *)&boot_cpu_data.x86_capability))
+    if (!test_bit(X86_FEATURE_PAT,
+            (volatile unsigned long *)&boot_cpu_data.x86_capability))
     {
         nv_printf(NV_DBG_ERRORS,
             "NVRM: CPU does not support the PAT, falling back to MTRRs.\n");
-        return 0;
+        return NV_PAT_MODE_DISABLED;
     }
 
     NV_READ_PAT_ENTRIES(pat1, pat2);
+    PAT_WC_index = 0xf;
 
     for (i = 0; i < 4; i++)
     {
-         // we plan to mark PAT entry 1 as WC. if it's already marked such,
-         // that's fine, since it would be no different than us setting it.
-         if ((i != 1) && NV_PAT_ENTRY(pat1, i) == 1)
-         {
-             nv_printf(NV_DBG_ERRORS, "NVRM: PAT index %d already configured for Write-Combining!\n", i);
-             nv_printf(NV_DBG_ERRORS, "NVRM: Aborting, due to PAT already being configured\n");
-             return 0;
-         }
-
-         if (NV_PAT_ENTRY(pat2, i) == 1)
-         {
-             nv_printf(NV_DBG_ERRORS, "NVRM: PAT index %d already configured for Write-Combining!\n", i + 4);
-             nv_printf(NV_DBG_ERRORS, "NVRM: Aborting, due to PAT already being configured\n");
-             return 0;
-         }
+        if (NV_PAT_ENTRY(pat1, i) == 0x01)
+        {
+            PAT_WC_index = i;
+            break;
+        }
+
+        if (NV_PAT_ENTRY(pat2, i) == 0x01)
+        {
+            PAT_WC_index = (i + 4);
+            break;
+        }
     }
 
-    return 1;
+    if (PAT_WC_index == 1)
+        return NV_PAT_MODE_KERNEL;
+    else if (PAT_WC_index != 0xf)
+    {
+        nv_printf(NV_DBG_ERRORS,
+            "NVRM: PAT configuration unsupported, falling back to MTRRs.\n");
+        return NV_PAT_MODE_DISABLED;
+    }
+    else
+        return NV_PAT_MODE_BUILTIN;
 }
 
 static unsigned long orig_pat1, orig_pat2;
@@ -978,19 +980,30 @@
     __nv_enable_caches(cr4);
     NV_RESTORE_FLAGS(eflags);
 }
-
-#endif /* defined(NV_BUILD_NV_PAT_SUPPORT) */
+#endif
 
 static int __nv_enable_pat_support()
 {
-#if defined(NV_BUILD_NV_PAT_SUPPORT)
+#if defined(NV_ENABLE_PAT_SUPPORT)
     unsigned long pat1, pat2;
 
-    if (nv_pat_enabled)
+    if (nv_pat_mode != NV_PAT_MODE_DISABLED)
         return 1;
 
-    if (!__check_pat_support())
-        return 0;
+    nv_pat_mode = __determine_pat_mode();
+
+    switch (nv_pat_mode)
+    {
+        case NV_PAT_MODE_DISABLED:
+            /* avoid the PAT if unavailable/unusable */
+            return 0;
+        case NV_PAT_MODE_KERNEL:
+            /* inherit the kernel's PAT layout */
+            return 1;
+        case NV_PAT_MODE_BUILTIN:
+            /* use builtin code to modify the PAT layout */
+            break;
+    }
 
     NV_READ_PAT_ENTRIES(orig_pat1, orig_pat2);
     nv_printf(NV_DBG_SETUP, "saved orig pats as 0x%lx 0x%lx\n", orig_pat1, orig_pat2);
@@ -1001,31 +1014,28 @@
         return 0;
     }
 
-    nv_pat_enabled = 1;
-
     NV_READ_PAT_ENTRIES(pat1, pat2);
     nv_printf(NV_DBG_SETUP, "changed pats to 0x%lx 0x%lx\n", pat1, pat2);
-#endif /* defined(NV_BUILD_NV_PAT_SUPPORT) */
-
+#endif
     return 1;
 }
 
 static void __nv_disable_pat_support()
 {
-#if defined(NV_BUILD_NV_PAT_SUPPORT)
+#if defined(NV_ENABLE_PAT_SUPPORT)
     unsigned long pat1, pat2;
 
-    if (!nv_pat_enabled)
+    if (nv_pat_mode != NV_PAT_MODE_BUILTIN)
         return;
 
     if (nv_execute_on_all_cpus(__nv_restore_pat_entries, NULL) != 0)
         return;
 
-    nv_pat_enabled = 0;
+    nv_pat_mode = NV_PAT_MODE_DISABLED;
 
     NV_READ_PAT_ENTRIES(pat1, pat2);
     nv_printf(NV_DBG_SETUP, "restored orig pats as 0x%lx 0x%lx\n", pat1, pat2);
-#endif /* defined(NV_BUILD_NV_PAT_SUPPORT) */
+#endif
 }
 
 #if defined(NV_CHANGE_PAGE_ATTR_BUG_PRESENT)
@@ -1273,7 +1283,7 @@
 #endif
 }
 
-#if defined(NV_BUILD_NV_PAT_SUPPORT) && defined(CONFIG_HOTPLUG_CPU)
+#if defined(NV_ENABLE_PAT_SUPPORT) && defined(CONFIG_HOTPLUG_CPU)
 static int
 nv_kern_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
 {
@@ -1305,8 +1315,7 @@
     .notifier_call = nv_kern_cpu_callback,
     .priority = 0
 };
-
-#endif /* defined(NV_BUILD_NV_PAT_SUPPORT) && defined(CONFIG_HOTPLUG_CPU) */
+#endif
 
 
 /***
@@ -1315,7 +1324,7 @@
 
 static int __init nvidia_init_module(void)
 {
-    int rc;
+    int rc, disable_pat = 0;
     U032 i, count, data;
     nv_state_t *nv = NV_STATE_PTR(&nv_ctl_device);
     nv_stack_t *sp = NULL;
@@ -1443,18 +1452,6 @@
         nv_printf(NV_DBG_ERRORS, "NVRM: pte cache allocation failed\n");
         goto failed;
     }
- 
-#if defined(NV_BUILD_NV_PAT_SUPPORT) && defined(CONFIG_HOTPLUG_CPU)
-    if (!nv_disable_pat)
-    {
-        if (register_hotcpu_notifier(&nv_hotcpu_nfb) != 0)
-        {
-            rc = -EIO;
-            nv_printf(NV_DBG_ERRORS, "NVRM: CPU hotplug notifier registration failed!\n");
-            goto failed;
-        }
-    }
-#endif
 
 #if defined(NV_SG_MAP_BUFFERS)
     rm_read_registry_dword(sp, nv, "NVreg", "RemapLimit", &nv_remap_limit);
@@ -1532,8 +1529,30 @@
 
     nvos_proc_add_warning_file("README", __README_warning);
 
-    if (!nv_disable_pat)
+    rc = rm_read_registry_dword(sp, nv,
+            "NVreg", NV_USE_PAGE_ATTRIBUTE_TABLE, &data);
+    if ((rc == 0) && ((int)data != ~0))
+    {
+        disable_pat = (data == 0);
+    }
+
+    if (!disable_pat)
+    {
         __nv_enable_pat_support();
+#if defined(NV_ENABLE_PAT_SUPPORT) && defined(CONFIG_HOTPLUG_CPU)
+        if (nv_pat_mode == NV_PAT_MODE_BUILTIN)
+        {
+            if (register_hotcpu_notifier(&nv_hotcpu_nfb) != 0)
+            {
+                __nv_disable_pat_support();
+                rc = -EIO;
+                nv_printf(NV_DBG_ERRORS,
+                        "NVRM: CPU hotplug notifier registration failed!\n");
+                goto failed;
+            }
+        }
+#endif
+    }
     else
     {
         nv_printf(NV_DBG_ERRORS,
@@ -1686,10 +1705,10 @@
     rm_unregister_compatible_ioctls(sp);
 #endif
 
-    if (nv_pat_enabled)
+    if (nv_pat_mode == NV_PAT_MODE_BUILTIN)
     {
         __nv_disable_pat_support();
-#if defined(NV_BUILD_NV_PAT_SUPPORT) && defined(CONFIG_HOTPLUG_CPU)
+#if defined(NV_ENABLE_PAT_SUPPORT) && defined(CONFIG_HOTPLUG_CPU)
         unregister_hotcpu_notifier(&nv_hotcpu_nfb);
 #endif
     }
@@ -1825,6 +1844,8 @@
     }
 }
 
+#if !defined(NV_VM_INSERT_PAGE_PRESENT)
+static
 struct page *nv_kern_vma_nopage(
     struct vm_area_struct *vma,
     unsigned long address,
@@ -1835,22 +1856,21 @@
 #endif
 )
 {
-#if !defined(NV_VM_INSERT_PAGE_PRESENT)
     struct page *page;
 
     page = pfn_to_page(vma->vm_pgoff);
     get_page(page);
 
     return page;
-#else
-    return NOPAGE_SIGBUS;
-#endif
 }
+#endif
 
 struct vm_operations_struct nv_vm_ops = {
     .open   = nv_kern_vma_open,
     .close  = nv_kern_vma_release,  /* "close" */
+#if !defined(NV_VM_INSERT_PAGE_PRESENT)
     .nopage = nv_kern_vma_nopage,
+#endif
 };
 
 static nv_file_private_t *
@@ -1864,7 +1884,7 @@
 
     memset(nvfp, 0, sizeof(nv_file_private_t));
 
-    sema_init(&nvfp->sp_lock, 1);
+    NV_INIT_MUTEX(&nvfp->sp_lock);
 
     // initialize this file's event queue
     init_waitqueue_head(&nvfp->waitqueue);
@@ -2214,11 +2234,12 @@
             break;
 #if defined(NVCPU_X86) || defined(NVCPU_X86_64)
         case NV_MEMORY_WRITECOMBINED:
-#if defined(NV_BUILD_NV_PAT_SUPPORT)
-            if (nv_pat_enabled &&
-                (memory_type != NV_MEMORY_TYPE_REGISTERS))
+#if defined(NV_ENABLE_PAT_SUPPORT)
+            if ((nv_pat_mode != NV_PAT_MODE_DISABLED) &&
+                    (memory_type != NV_MEMORY_TYPE_REGISTERS))
             {
-                *prot = pgprot_writecombined(*prot);
+                pgprot_val(*prot) &= ~(_PAGE_PSE | _PAGE_PCD | _PAGE_PWT);
+                *prot = __pgprot(pgprot_val(*prot) | _PAGE_PWT);
                 break;
             }
 #endif
@@ -2242,7 +2263,6 @@
             return 1;
 #endif
         case NV_MEMORY_CACHED:
-        //case NV_MEMORY_WRITEBACK:
 #if !defined(NVCPU_X86) && !defined(NVCPU_X86_64)
             if (memory_type != NV_MEMORY_TYPE_REGISTERS)
                 break;
@@ -2264,8 +2284,6 @@
             if (memory_type == NV_MEMORY_TYPE_SYSTEM)
                 break;
 #endif
-        //case NV_MEMORY_WRITETHRU:
-        //case NV_MEMORY_WRITEPROTECT:
         default:
             if(nv_ext_encode_caching(prot, cache_type, memory_type) == 0)
                 return 0;
@@ -3502,6 +3520,10 @@
     BOOL kern
 )
 {
+#if defined(NV_SET_PAGES_UC_PRESENT) && defined(NVCPU_X86)
+    nv_printf(NV_DBG_ERRORS,
+        "NVRM: can't translate address in nv_get_phys_address()!\n");
+#else
     struct mm_struct *mm;
     pgd_t *pgd = NULL;
     pmd_t *pmd = NULL;
@@ -3514,15 +3536,7 @@
         down_read(&mm->mmap_sem);
     }
     else
-    {
-#if defined(NV_SET_PAGES_UC_PRESENT) && defined(NVCPU_X86)
-        nv_printf(NV_DBG_ERRORS,
-            "NVRM: can't translate KVA in nv_get_phys_address()!\n");
-        return 0;
-#else
         mm = NULL;
-#endif
-    }
 
     pgd = NV_PGD_OFFSET(address, kern, mm);
     if (!NV_PGD_PRESENT(pgd))
@@ -3550,6 +3564,7 @@
 failed:
     if (!kern)
         up_read(&mm->mmap_sem);
+#endif
     return 0;
 }
 
@@ -3790,8 +3805,9 @@
 
     nv_init_lock(nvl->rm_lock);
 
-    sema_init(&nvl->ldata_lock, 1);
-    sema_init(&nvl->at_lock, 1);
+    NV_INIT_MUTEX(&nvl->ldata_lock);
+    NV_INIT_MUTEX(&nvl->at_lock);
+
     NV_ATOMIC_SET(nvl->usage_count, 0);
 
     nvl->rm_lock_cpu = -1;
diff -ru usr/src/nv/os-agp.c usr/src/nv.2419292/os-agp.c
--- usr/src/nv/os-agp.c	2008-05-19 00:37:01.000000000 -0700
+++ usr/src/nv.2419292/os-agp.c	2008-05-21 12:07:30.437656163 -0700
@@ -115,7 +115,7 @@
         goto release;
     }
 
-    if (!nv_pat_enabled)
+    if (nv_pat_mode == NV_PAT_MODE_DISABLED)
     {
 #ifdef CONFIG_MTRR
         /*
@@ -175,7 +175,7 @@
 
 failed:
 #ifdef CONFIG_MTRR
-    if (!nv_pat_enabled)
+    if (nv_pat_mode == NV_PAT_MODE_DISABLED)
         mtrr_del(-1, agp_info.aper_base, agp_info.aper_size << 20);
 #endif
 release:
@@ -205,7 +205,7 @@
     nvl = NV_GET_NVL_FROM_NV_STATE(nv);
 
 #ifdef CONFIG_MTRR
-    if (!nv_pat_enabled)
+    if (nv_pat_mode == NV_PAT_MODE_DISABLED)
         mtrr_del(-1, nv->agp.address, nv->agp.size);
 #endif
 
diff -ru usr/src/nv/os-interface.c usr/src/nv.2419292/os-interface.c
--- usr/src/nv/os-interface.c	2008-05-19 00:37:01.000000000 -0700
+++ usr/src/nv.2419292/os-interface.c	2008-05-21 12:07:33.365823028 -0700
@@ -1355,7 +1355,7 @@
 
 BOOL NV_API_CALL os_pat_supported(void)
 {
-    return nv_pat_enabled;
+    return (nv_pat_mode != NV_PAT_MODE_DISABLED);
 }
 
 void NV_API_CALL os_dump_stack()