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Commit a9acc536 authored by Jesse Barnes's avatar Jesse Barnes Committed by H. Peter Anvin
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x86/Sandy Bridge: reserve pages when integrated graphics is present 



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.

[ hpa: made a number of stylistic changes, marked arrays as static
  const, and made less verbose; use "memblock=debug" for full
  verbosity. ]

Signed-off-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
parent 886d751a

arch/x86/kernel/setup.c

+78 −0
Original line number Diff line number Diff line
@@ -610,6 +610,81 @@ 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;

	static const 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;

}



/*

 * Sandy Bridge graphics has trouble with certain ranges, exclude

 * them from allocation.

 */

static void __init trim_snb_memory(void)

{

	static const unsigned long bad_pages[] = {

		0x20050000,

		0x20110000,

		0x20130000,

		0x20138000,

		0x40004000,

	};

	int i;



	if (!snb_gfx_workaround_needed())

		return;



	printk(KERN_DEBUG "reserving inaccessible SNB gfx pages\n");



	/*

	 * Reserve all memory below the 1 MB mark that has not

	 * already been reserved.

	 */

	memblock_reserve(0, 1<<20);

	

	for (i = 0; i < ARRAY_SIZE(bad_pages); i++) {

		if (memblock_reserve(bad_pages[i], PAGE_SIZE))

			printk(KERN_WARNING "failed to reserve 0x%08lx\n",

			       bad_pages[i]);

	}

}



/*

 * Here we put platform-specific memory range workarounds, i.e.

 * memory known to be corrupt or otherwise in need to be reserved on

 * specific platforms.

 *

 * If this gets used more widely it could use a real dispatch mechanism.

 */

static void __init trim_platform_memory_ranges(void)

{

	trim_snb_memory();

}



static void __init trim_bios_range(void)

{

	/*
@@ -630,6 +705,7 @@ 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);

}
@@ -908,6 +984,8 @@ void __init setup_arch(char **cmdline_p) 


	setup_real_mode();



	trim_platform_memory_ranges();



	init_gbpages();



	/* max_pfn_mapped is updated here */