Aaron Durbin (adurbin@google.com) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/2894
-gerrit
commit 59176197e10b3498b5bf99773be183dddb317334 Author: Aaron Durbin adurbin@chromium.org Date: Fri Mar 22 22:25:37 2013 -0500
sandybridge: add option to mark graphics memory write-combining.
The graphics memory can be accessed in a faster manner by setting it to write-combing mode. Add an option to enable write-combining for the graphics memory.
Change-Id: I7d37fd78906262aabef92c2b4f4cab0e3f7e4f6d Signed-off-by: Aaron Durbin adurbin@chromium.org --- src/northbridge/intel/sandybridge/Kconfig | 8 ++++++++ src/northbridge/intel/sandybridge/gma.c | 19 ++++++++++++++++++- 2 files changed, 26 insertions(+), 1 deletion(-)
diff --git a/src/northbridge/intel/sandybridge/Kconfig b/src/northbridge/intel/sandybridge/Kconfig index 56d2cd7..6c9ae99 100644 --- a/src/northbridge/intel/sandybridge/Kconfig +++ b/src/northbridge/intel/sandybridge/Kconfig @@ -107,6 +107,14 @@ config DCACHE_RAM_MRC_VAR_SIZE hex default 0x4000
+config MARK_GRAPHICS_MEM_WRCOMB + bool "Mark graphics memory as write-combining." + default n + help + The graphics performance may increase if the graphics + memory is set as write-combining cache type. This option + enables marking the graphics memory as write-combining. + config HAVE_MRC bool "Add a System Agent binary" help diff --git a/src/northbridge/intel/sandybridge/gma.c b/src/northbridge/intel/sandybridge/gma.c index b9a07a2..853139e 100644 --- a/src/northbridge/intel/sandybridge/gma.c +++ b/src/northbridge/intel/sandybridge/gma.c @@ -664,12 +664,29 @@ static void gma_set_subsystem(device_t dev, unsigned vendor, unsigned device) } }
+static void gma_read_resources(struct device *dev) +{ + pci_dev_read_resources(dev); + +#if CONFIG_MARK_GRAPHICS_MEM_WRCOMB + struct resource *res; + + /* Set the graphics memory to write combining. */ + res = find_resource(dev, PCI_BASE_ADDRESS_2); + if (res == NULL) { + printk(BIOS_DEBUG, "gma: memory resource not found.\n"); + return; + } + res->flags |= IORESOURCE_WRCOMB; +#endif +} + static struct pci_operations gma_pci_ops = { .set_subsystem = gma_set_subsystem, };
static struct device_operations gma_func0_ops = { - .read_resources = pci_dev_read_resources, + .read_resources = gma_read_resources, .set_resources = pci_dev_set_resources, .enable_resources = pci_dev_enable_resources, .init = gma_func0_init,