Some more additional information:

All that is needed to fix the driver is changeset 4dd00681dd0f9fce8dfd4592b46418edbbd2eeb4 out of the xf86-video-intel git tree. Unfortunately this also requires the kernel fix to work (82e14a6215cbc9804ecc35281e973c6c8ce22fe7 out of linus repository).

Both fixes are quite contained to the specific hardware and fix it to work on more cards. I guess its still no reason for a freeze exception?


X driver:
commit 4dd00681dd0f9fce8dfd4592b46418edbbd2eeb4
Author: Eric Anholt <email address hidden>
Date:   Tue Oct 14 11:33:33 2008 -0700

    Fix broken stolen memory counting on G4X.
    
    On the GM45 we were assuming too little stolen memory (mostly harmless,
    except when it wasn't, until the AGP fix), and on the G45 we were assuming too
    much stolen memory, which was quite harmful when we touched the page that
    didn't get mapped.
    
    Future stolen memory accounting should use src/reg_dumper/intel_gtt before and
    after enabling AGP on the chipset to confirm that only the GTT entries not
    mapped to stolen are replaced, and that all of the unmapped GTT entries are
    replaced with the constant scratch page.

diff --git a/src/i830_driver.c b/src/i830_driver.c
index c1d61f4..eaf5d27 100644
--- a/src/i830_driver.c
+++ b/src/i830_driver.c
@@ -502,8 +502,8 @@ I830DetectMemory(ScrnInfoPtr pScrn)
    range = gtt_size + 4;
 
    /* new 4 series hardware has seperate GTT stolen with GFX stolen */
-   if (IS_G4X(pI830))
-       range = 0;
+   if (IS_G4X(pI830) || IS_GM45(pI830))
+       range = 4;
 
    if (IS_I85X(pI830) || IS_I865G(pI830) || IS_I9XX(pI830)) {
       switch (gmch_ctrl & I855_GMCH_GMS_MASK) {

Kernel: 
commit 82e14a6215cbc9804ecc35281e973c6c8ce22fe7
Author: Eric Anholt <email address hidden>
Date:   Tue Oct 14 11:28:58 2008 -0700

    agp: Fix stolen memory counting on G4X.
    
    On the GM45, the amount of stolen memory mapped to the GTT was underestimated,
    even though we had 508KB more available since the GTT doesn't take from
    stolen memory. On the non-GM45 G4X, we overestimated how much stolen was
    mapped to the GTT by 4KB, resulting in GPU page faults when that page was
    accessed.
    
    This update requires a corresponding update to xf86-video-intel to work
    correctly.
    
    Signed-off-by: Eric Anholt <email address hidden>
    Signed-off-by: Dave Airlie <email address hidden>

diff --git a/drivers/char/agp/intel-agp.c b/drivers/char/agp/intel-agp.c
index 016fdf0..f1fe749 100644
--- a/drivers/char/agp/intel-agp.c
+++ b/drivers/char/agp/intel-agp.c
@@ -54,8 +54,7 @@
 		 agp_bridge->dev->device == PCI_DEVICE_ID_INTEL_82965Q_HB || \
 		 agp_bridge->dev->device == PCI_DEVICE_ID_INTEL_82965G_HB || \
 		 agp_bridge->dev->device == PCI_DEVICE_ID_INTEL_82965GM_HB || \
-		 agp_bridge->dev->device == PCI_DEVICE_ID_INTEL_82965GME_HB || \
-		 agp_bridge->dev->device == PCI_DEVICE_ID_INTEL_GM45_HB)
+		 agp_bridge->dev->device == PCI_DEVICE_ID_INTEL_82965GME_HB)
 
 #define IS_G33 (agp_bridge->dev->device == PCI_DEVICE_ID_INTEL_G33_HB || \
 		agp_bridge->dev->device == PCI_DEVICE_ID_INTEL_Q35_HB || \
@@ -63,7 +62,8 @@
 
 #define IS_G4X (agp_bridge->dev->device == PCI_DEVICE_ID_INTEL_IGD_E_HB || \
 		agp_bridge->dev->device == PCI_DEVICE_ID_INTEL_Q45_HB || \
-		agp_bridge->dev->device == PCI_DEVICE_ID_INTEL_G45_HB)
+		agp_bridge->dev->device == PCI_DEVICE_ID_INTEL_G45_HB || \
+		agp_bridge->dev->device == PCI_DEVICE_ID_INTEL_GM45_HB)
 
 extern int agp_memory_reserved;
 
@@ -525,8 +525,10 @@ static void intel_i830_init_gtt_entries(void)
 		size += 4;
 	} else if (IS_G4X) {
 		/* On 4 series hardware, GTT stolen is separate from graphics
-		 * stolen, ignore it in stolen gtt entries counting */
-		size = 0;
+		 * stolen, ignore it in stolen gtt entries counting.  However,
+		 * 4KB of the stolen memory doesn't get mapped to the GTT.
+		 */
+		size = 4;
 	} else {
 		/* On previous hardware, the GTT size was just what was
 		 * required to map the aperture.


Andres