SNB graphics devices have a bug that prevent them from accessing certain
memory ranges, namely anything below 1M and in the pages listed in the
table. So reserve those at boot if set detect a SNB gfx device on the
CPU to avoid GPU hangs.
Stephane Marchesin had a similar patch to the page allocator awhile
back, but rather than reserving pages up front, it leaked them at
allocation time.
Signed-off-by: Jesse Barnes <jbarnes at virtuousgeek.org>
---
arch/x86/kernel/setup.c | 72 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 72 insertions(+)
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 468e98d..bb9fabe 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -614,6 +614,75 @@ static __init void reserve_ibft_region(void)
static unsigned reserve_low = CONFIG_X86_RESERVE_LOW << 10;
+static bool __init snb_gfx_workaround_needed(void)
+{
+ int i;
+ u16 vendor, devid;
+ u16 snb_ids[] = {
+ 0x0102,
+ 0x0112,
+ 0x0122,
+ 0x0106,
+ 0x0116,
+ 0x0126,
+ 0x010a,
+ };
+
+ /* Assume no if something weird is going on with PCI */
+ if (!early_pci_allowed())
+ return false;
+
+ vendor = read_pci_config_16(0, 2, 0, PCI_VENDOR_ID);
+ if (vendor != 0x8086)
+ return false;
+
+ devid = read_pci_config_16(0, 2, 0, PCI_DEVICE_ID);
+ for (i = 0; i < ARRAY_SIZE(snb_ids); i++)
+ if (devid == snb_ids[i])
+ return true;
+
+ return false;
+}
+
+static void __init trim_snb_ranges(void)
+{
+ /*
+ * Sandy Bridge graphics has trouble with certain ranges, exclude
+ * them from allocation.
+ */
+ if (snb_gfx_workaround_needed()) {
+ unsigned long bad_ranges[] = {
+ 0x20050000,
+ 0x20110000,
+ 0x20130000,
+ 0x20138000,
+ 0x40004000,
+ };
+ phys_addr_t mem;
+ int i;
+
+ printk(KERN_DEBUG "reserving inaccessible SNB gfx pages\n");
+
+ for (;;) {
+ mem = memblock_find_in_range(0, 1<<20, PAGE_SIZE,
+ PAGE_SIZE);
+ if (!mem)
+ break;
+ memblock_reserve(mem, PAGE_SIZE);
+ printk(KERN_DEBUG "reserved 0x%08lx\n", mem);
+ }
+
+ for (i = 0; i < ARRAY_SIZE(bad_ranges); i++) {
+ if (!memblock_reserve(bad_ranges[i], PAGE_SIZE))
+ printk(KERN_DEBUG "reserved 0x%08lx\n",
+ bad_ranges[i]);
+ else
+ printk(KERN_DEBUG "failed to reserve 0x%08lx\n",
+ bad_ranges[i]);
+ }
+ }
+}
+
static void __init trim_bios_range(void)
{
/*
@@ -634,6 +703,7 @@ static void __init trim_bios_range(void)
* take them out.
*/
e820_remove_range(BIOS_BEGIN, BIOS_END - BIOS_BEGIN, E820_RAM, 1);
+
sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
}
@@ -912,6 +982,8 @@ void __init setup_arch(char **cmdline_p)
setup_real_mode();
+ trim_snb_ranges();
+
init_gbpages();
/* max_pfn_mapped is updated here */
--
1.7.9.5
