intel/agp: rewrite GTT on resume

On my Intel chipset (965GM), the GTT is entirely erased across
suspend/resume.  This patch simply re-plays the current mapping at resume
time to restore the table.=20

I noticed this once I started relying on persistent GTT mappings across VT
switch in our GEM work -- the old X server and DRM code carefully unbind
all memory from the GTT on VT switch, but GEM does not bother.

I placed the list management and rewrite code in the generic layer on the
assumption that it will be needed on other hardware, but I did not add the
rewrite call to anything other than the Intel resume function.

Keep a list of current GATT mappings.  At resume time, rewrite them into
the GATT.  This is needed on Intel (at least) as the entire GATT is
cleared across suspend/resume.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Keith Packard <keithp@keithp.com>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>

4 files changed, 38 insertions, 0 deletions

diff --git a/drivers/char/agp/agp.h b/drivers/char/agp/agp.h
index 81e14bea54b..4bada0e8b81 100644
--- a/drivers/char/agp/agp.h
+++ b/drivers/char/agp/agp.h
@@ -148,6 +148,9 @@ struct agp_bridge_data {
         char minor_version;
         struct list_head list;
         u32 apbase_config;
+        /* list of agp_memory mapped to the aperture */
+        struct list_head mapped_list;
+        spinlock_t mapped_lock;
 };
 
 #define KB(x)   ((x) * 1024)
diff --git a/drivers/char/agp/backend.c b/drivers/char/agp/backend.c
index 9626d3bda09..3a3cc03d401 100644
--- a/drivers/char/agp/backend.c
+++ b/drivers/char/agp/backend.c
@@ -185,6 +185,8 @@ static int agp_backend_initialize(struct agp_bridge_data *bridge)
                 rc = -EINVAL;
                 goto err_out;
         }
+        INIT_LIST_HEAD(&bridge->mapped_list);
+        spin_lock_init(&bridge->mapped_lock);
 
         return 0;
 
diff --git a/drivers/char/agp/generic.c b/drivers/char/agp/generic.c
index 54c91000646..118dbde25dc 100644
--- a/drivers/char/agp/generic.c
+++ b/drivers/char/agp/generic.c
@@ -429,6 +429,10 @@ int agp_bind_memory(struct agp_memory *curr, off_t pg_start)
 
         curr->is_bound = true;
         curr->pg_start = pg_start;
+        spin_lock(&agp_bridge->mapped_lock);
+        list_add(&curr->mapped_list, &agp_bridge->mapped_list);
+        spin_unlock(&agp_bridge->mapped_lock);
+
         return 0;
 }
 EXPORT_SYMBOL(agp_bind_memory);
@@ -461,10 +465,34 @@ int agp_unbind_memory(struct agp_memory *curr)
 
         curr->is_bound = false;
         curr->pg_start = 0;
+        spin_lock(&curr->bridge->mapped_lock);
+        list_del(&curr->mapped_list);
+        spin_unlock(&curr->bridge->mapped_lock);
         return 0;
 }
 EXPORT_SYMBOL(agp_unbind_memory);
 
+/**
+ *      agp_rebind_emmory  -  Rewrite the entire GATT, useful on resume
+ */
+int agp_rebind_memory(void)
+{
+        struct agp_memory *curr;
+        int ret_val = 0;
+
+        spin_lock(&agp_bridge->mapped_lock);
+        list_for_each_entry(curr, &agp_bridge->mapped_list, mapped_list) {
+                ret_val = curr->bridge->driver->insert_memory(curr,
+                                                              curr->pg_start,
+                                                              curr->type);
+                if (ret_val != 0)
+                        break;
+        }
+        spin_unlock(&agp_bridge->mapped_lock);
+        return ret_val;
+}
+EXPORT_SYMBOL(agp_rebind_memory);
+
 /* End - Routines for handling swapping of agp_memory into the GATT */
 
 
diff --git a/drivers/char/agp/intel-agp.c b/drivers/char/agp/intel-agp.c
index 57c552ee046..016fdf0623a 100644
--- a/drivers/char/agp/intel-agp.c
+++ b/drivers/char/agp/intel-agp.c
@@ -2244,6 +2244,7 @@ static void __devexit agp_intel_remove(struct pci_dev *pdev)
 static int agp_intel_resume(struct pci_dev *pdev)
 {
         struct agp_bridge_data *bridge = pci_get_drvdata(pdev);
+        int ret_val;
 
         pci_restore_state(pdev);
 
@@ -2271,6 +2272,10 @@ static int agp_intel_resume(struct pci_dev *pdev)
         else if (bridge->driver == &intel_i965_driver)
                 intel_i915_configure();
 
+        ret_val = agp_rebind_memory();
+        if (ret_val != 0)
+                return ret_val;
+
         return 0;
 }
 #endif