Re: linux-next: Tree for Apr 9 (x86 boot problem)

Randy Dunlap
2021-04-13T17:34:39Z

On 4/13/21 9:58 AM, Mike Rapoport wrote:
> On Mon, Apr 12, 2021 at 11:21:48PM -0700, Randy Dunlap wrote:
>> On 4/12/21 11:06 PM, Mike Rapoport wrote:
>>> Hi Randy,
>>>
>>> On Mon, Apr 12, 2021 at 01:53:34PM -0700, Randy Dunlap wrote:
>>>> On 4/12/21 10:01 AM, Mike Rapoport wrote:
>>>>> On Mon, Apr 12, 2021 at 08:49:49AM -0700, Randy Dunlap wrote:
>>>>>
>>>>> I thought about adding some prints to see what's causing the hang, the
>>>>> reservations or their absence. Can you replace the debug patch with this
>>>>> one:
>>>>>
>>>>> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
>>>>> index 776fc9b3fafe..a10ac252dbcc 100644
>>>>> --- a/arch/x86/kernel/setup.c
>>>>> +++ b/arch/x86/kernel/setup.c
>>>>> @@ -600,10 +600,13 @@ static bool __init snb_gfx_workaround_needed(void)
>>>>> return false;
>>>>>
>>>>> vendor = read_pci_config_16(0, 2, 0, PCI_VENDOR_ID);
>>>>> + devid = read_pci_config_16(0, 2, 0, PCI_DEVICE_ID);
>>>>> +
>>>>> + pr_info("%s: vendor: %x, device: %x\n", __func__, vendor, device);
>>>>
>>>> s/device)/devid)/
>>>
>>> Oh, sorry.
>>>
>>>>> +
>>>>> 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;
>>>>
>>>> That prints:
>>>>
>>>> [ 0.000000] snb_gfx_workaround_needed: vendor: 8086, device: 126
>>>> [ 0.000000] early_reserve_memory: snb_gfx: 1
>>>> ...
>>>> [ 0.014061] snb_gfx_workaround_needed: vendor: 8086, device: 126
>>>> [ 0.014064] reserving inaccessible SNB gfx pages
>>>>
>>>>
>>>> The full boot log is attached.
>>>
>>> Can you please send the log with memblock=debug added to the kernel command
>>> line?
>>>
>>> Probably should have started from this...
>>>
>>
>> It's attached.
>
> Honestly, I can't see any reason why moving these reservations around would
> cause your laptop to hang.
> Let's try moving the reservations back to their original place one by
> one, e.g something like this:
>
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index 776fc9b3fafe..892ad20b8557 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -632,12 +632,6 @@ static void __init trim_snb_memory(void)
>
> 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",
> @@ -1081,6 +1075,12 @@ void __init setup_arch(char **cmdline_p)
>
> reserve_real_mode();
>
> + /*
> + * Reserve all memory below the 1 MB mark that has not
> + * already been reserved.
> + */
> + memblock_reserve(0, 1<<20);
> +
> init_mem_mapping();
>
> idt_setup_early_pf();
>

Mike,
That works.

Please send the next test.

--
~Randy