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agp/intel: Experiment with a 855GM GWB bit

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Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=27187
Tested-by: Thorsten Vollmer <thorsten@thvo.de> (DFI-ACP G5M150-N w/852GME)
Tested-by: Moritz Brunner <2points@gmx.org> (Asus M2400N/i855GM)
Tested-by: Indan Zupancic <indan@nul.nu> (Thinkpad X40/855GM rev 02)
Tested-by: Eric Anholt <eric@anholt.net> (865G)
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
This commit is contained in:
Chris Wilson 2010-12-22 11:37:09 +00:00
parent a36dbec57e
commit bdb8b975fc
2 changed files with 22 additions and 35 deletions
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1
drivers/char/agp/intel-agp.h
View File

@ -130,6 +130,7 @@
#define INTEL_GMCH_GMS_STOLEN_352M (0xd << 4)
#define I915_IFPADDR 0x60
#define I830_HIC 0x70
/* Intel 965G registers */
#define I965_MSAC 0x62

56
drivers/char/agp/intel-gtt.c
View File

@ -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"
@ -70,12 +71,8 @@ static struct _intel_private {
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;
@ -722,28 +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
@ -758,14 +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);
memset(pg, 0, 1024);
/* Forcibly evict everything from the CPU write buffers.
* clflush appears to be insufficient.
*/
wbinvd_on_all_cpus();
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");
/* 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);
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,
@ -849,8 +837,6 @@ static int i830_setup(void)
intel_private.gtt_bus_addr = reg_addr + I810_PTE_BASE;
intel_i830_setup_flush();
return 0;
}