1 files changed, 30 insertions, 45 deletions

diff --git a/drivers/char/agp/intel-gtt.c b/drivers/char/agp/intel-gtt.c
index 826ab0939a12..0d09b537bb9a 100644
--- a/drivers/char/agp/intel-gtt.c
+++ b/drivers/char/agp/intel-gtt.c
@@ -21,6 +21,7 @@
 #include <linux/kernel.h>
 #include <linux/pagemap.h>
 #include <linux/agp_backend.h>
+#include <linux/delay.h>
 #include <asm/smp.h>
 #include "agp.h"
 #include "intel-agp.h"
@@ -68,13 +69,10 @@ static struct _intel_private {
         phys_addr_t gma_bus_addr;
         u32 PGETBL_save;
         u32 __iomem *gtt;               /* I915G */
+        bool clear_fake_agp; /* on first access via agp, fill with scratch */
         int num_dcache_entries;
-        union {
-                void __iomem *i9xx_flush_page;
-                void *i8xx_flush_page;
-        };
+        void __iomem *i9xx_flush_page;
         char *i81x_gtt_table;
-        struct page *i8xx_page;
         struct resource ifp_resource;
         int resource_valid;
         struct page *scratch_page;
@@ -721,28 +719,6 @@ static int intel_fake_agp_fetch_size(void)
 
 static void i830_cleanup(void)
 {
-        if (intel_private.i8xx_flush_page) {
-                kunmap(intel_private.i8xx_flush_page);
-                intel_private.i8xx_flush_page = NULL;
-        }
-
-        __free_page(intel_private.i8xx_page);
-        intel_private.i8xx_page = NULL;
-}
-
-static void intel_i830_setup_flush(void)
-{
-        /* return if we've already set the flush mechanism up */
-        if (intel_private.i8xx_page)
-                return;
-
-        intel_private.i8xx_page = alloc_page(GFP_KERNEL);
-        if (!intel_private.i8xx_page)
-                return;
-
-        intel_private.i8xx_flush_page = kmap(intel_private.i8xx_page);
-        if (!intel_private.i8xx_flush_page)
-                i830_cleanup();
 }
 
 /* The chipset_flush interface needs to get data that has already been
@@ -757,14 +733,27 @@ static void intel_i830_setup_flush(void)
  */
 static void i830_chipset_flush(void)
 {
-        unsigned int *pg = intel_private.i8xx_flush_page;
+        unsigned long timeout = jiffies + msecs_to_jiffies(1000);
+
+        /* Forcibly evict everything from the CPU write buffers.
+         * clflush appears to be insufficient.
+         */
+        wbinvd_on_all_cpus();
 
-        memset(pg, 0, 1024);
+        /* Now we've only seen documents for this magic bit on 855GM,
+         * we hope it exists for the other gen2 chipsets...
+         *
+         * Also works as advertised on my 845G.
+         */
+        writel(readl(intel_private.registers+I830_HIC) | (1<<31),
+               intel_private.registers+I830_HIC);
 
-        if (cpu_has_clflush)
-                clflush_cache_range(pg, 1024);
-        else if (wbinvd_on_all_cpus() != 0)
-                printk(KERN_ERR "Timed out waiting for cache flush.\n");
+        while (readl(intel_private.registers+I830_HIC) & (1<<31)) {
+                if (time_after(jiffies, timeout))
+                        break;
+
+                udelay(50);
+        }
 }
 
 static void i830_write_entry(dma_addr_t addr, unsigned int entry,
@@ -848,8 +837,6 @@ static int i830_setup(void)
 
         intel_private.gtt_bus_addr = reg_addr + I810_PTE_BASE;
 
-        intel_i830_setup_flush();
-
         return 0;
 }
 
@@ -869,21 +856,12 @@ static int intel_fake_agp_free_gatt_table(struct agp_bridge_data *bridge)
 
 static int intel_fake_agp_configure(void)
 {
-        int i;
-
         if (!intel_enable_gtt())
             return -EIO;
 
+        intel_private.clear_fake_agp = true;
         agp_bridge->gart_bus_addr = intel_private.gma_bus_addr;
 
-        for (i = 0; i < intel_private.base.gtt_total_entries; i++) {
-                intel_private.driver->write_entry(intel_private.scratch_page_dma,
-                                                  i, 0);
-        }
-        readl(intel_private.gtt+i-1);   /* PCI Posting. */
-
-        global_cache_flush();
-
         return 0;
 }
 
@@ -945,6 +923,13 @@ static int intel_fake_agp_insert_entries(struct agp_memory *mem,
 {
         int ret = -EINVAL;
 
+        if (intel_private.clear_fake_agp) {
+                int start = intel_private.base.stolen_size / PAGE_SIZE;
+                int end = intel_private.base.gtt_mappable_entries;
+                intel_gtt_clear_range(start, end - start);
+                intel_private.clear_fake_agp = false;
+        }
+
         if (INTEL_GTT_GEN == 1 && type == AGP_DCACHE_MEMORY)
                 return i810_insert_dcache_entries(mem, pg_start, type);