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Date: Sun, 13 Jan 2013 21:30:52 +0100
From: Mathias Krause <minipli@...glemail.com>
To: hpa@...ux.intel.com
Cc: linux-kernel@...r.kernel.org, mingo@...nel.org, hpa@...or.com,
tglx@...utronix.de, linux-tip-commits@...r.kernel.org,
Stéphane Marchesin <marcheu@...omium.org>,
Jesse Barnes <jbarnes@...tuousgeek.org>
Subject: Re: [tip:x86/urgent] x86/Sandy Bridge: reserve pages when integrated graphics is present
Hi Peter,
Am 12.01.2013 um 00:00 schrieb Jesse Barnes <jbarnes@...tuousgeek.org>:
> On Fri, 11 Jan 2013 14:39:04 -0800
> tip-bot for Jesse Barnes <jbarnes@...tuousgeek.org> wrote:
>
>> Commit-ID: a9acc5365dbda29f7be2884efb63771dc24bd815
>> Gitweb: http://git.kernel.org/tip/a9acc5365dbda29f7be2884efb63771dc24bd815
>> Author: Jesse Barnes <jbarnes@...tuousgeek.org>
>> AuthorDate: Wed, 14 Nov 2012 20:43:31 +0000
>> Committer: H. Peter Anvin <hpa@...ux.intel.com>
>> CommitDate: Fri, 11 Jan 2013 14:26:38 -0800
>>
>> 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. ]
That stylistic change introduced the unwanted side effect of leaving the tables in memory after __init cleanup. But that can be fixed, see below :)
>>
>> Signed-off-by: Jesse Barnes <jbarnes@...tuousgeek.org>
>> Signed-off-by: H. Peter Anvin <hpa@...ux.intel.com>
>> ---
>> arch/x86/kernel/setup.c | 78 +++++++++++++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 78 insertions(+)
>>
>> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
>> index 23ddd55..9dcb325 100644
>> --- a/arch/x86/kernel/setup.c
>> +++ b/arch/x86/kernel/setup.c
>> @@ -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[] = {
__initconst is missing here
>> + 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[] = {
here, too
>> + 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 */
>>
Regards,
Mathias--
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