01.12.2015 11:34, Vitaly Kuznetsov пишет:
> Michael Chang <mch...@suse.com> writes:
>
>> On Mon, Nov 30, 2015 at 08:34:18PM +0300, Andrei Borzenkov wrote:
>>> 30.11.2015 19:50, Andrei Borzenkov пишет:
>>>> 30.11.2015 19:31, Vitaly Kuznetsov пишет:
>>>>> Andrei Borzenkov <arvidj...@gmail.com> writes:
>>>>>
>>>>>> 26.11.2014 11:59, Laszlo Ersek пишет:
>>>>>>> HyperV Gen2 virtual machines have no PIT; guest code should rely on UEFI
>>>>>>> services instead.
>>>>>>>
>>>>>>
>>>>>> Could you retest with current master? It now supports multiple methods
>>>>>> to calibrate TSC and should avoid PIT on UEFI systems.
>>>>>
>>>>> Unfortunately, current master (grub-2.02-beta2-561-g346a494) still
>>>>> doesn't work for me, timer keeps running like crazy on Gen2 Hyper-V VMs.
>>>>>
>>>>
>>>> @Michael: I remember you tested version of Vladimir patch on Hyper-V?
>>>> Could you test current master?
>>>>
>>
>> I don't have access to Hyper-V either. My initial patch was tested on
>> Hyper-V from my colleage in Nuremburg. For Vladimir's patch I did tests
>> on my EFI machine and mostly intersted in pmtimer to function properly,
>> as that's new introduced timer to the patch ..
>>
>>>
>>>
>>> if ((grub_inb (GRUB_PIT_SPEAKER_PORT) & GRUB_PIT_SPK_TMR2_LATCH)) {
>>> ret = 1;
>>> /* Wait. */
>>> while ((grub_inb (GRUB_PIT_SPEAKER_PORT) & GRUB_PIT_SPK_TMR2_LATCH)
>>> == 0x00);
>>> }
>>>
>>>
>>> If PIT is not present all reads should return 0xff so this will always
>>> succeed, right? Linux kernel is using some sanity checks, if loop
>>> terminated too early it assumes calibration failure.
>>
>> Well, yes the detection is bogus, I think the condition should check for
>> return 0x00, which means the timer is counting and can continue to wait
>> for it to finish.
>>
>> if ((grub_inb (GRUB_PIT_SPEAKER_PORT) & GRUB_PIT_SPK_TMR2_LATCH) == 0) {
>> ret = 1;
>> /* Wait. */
>> while ((grub_inb (GRUB_PIT_SPEAKER_PORT) & GRUB_PIT_SPK_TMR2_LATCH)
>> == 0x00);
>> }
>>
>> Vitaly, could you please help to retest ?
>>
>
> Sure,
>
> just did and with this change timer seems to be working as expected.
>
Thank you! I pushed fix, if you could verify that master now works on
Hyper-V would be great.
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