Re: [PATCH v6 0/3] PCI: Precision Time Measurement support

From: Yong, Jonathan
Date: Tue Jul 19 2016 - 19:49:29 EST


On 07/20/2016 05:19, Bjorn Helgaas wrote:
> On Mon, Jun 13, 2016 at 02:05:26PM -0500, Bjorn Helgaas wrote:
>> This is a slightly different proposal for the PTM support Jonathan
>> proposed here:
>>
>> http://lkml.kernel.org/r/1462956446-27361-2-git-send-email-jonathan.yong@xxxxxxxxx
>>
>> I split this into three pieces mostly for ease in reviewing. They
>> could all be squashed:
>>
>> - Enable PTM in root ports and switches automatically at boot
>> - Enable PTM in endpoints when requested by driver
>> - Add clock granularity information
>>
>> I have some open questions about how PTM works on Root Complex
>> Integrated Endpoints and whether we should enable it automatically
>> even without a driver request. And I probably left out some details
>> of the clock granularity computation, so treat this as more of an RFC
>> than anything.
>>
>
> Jonathan, any comments?
>

I don't have any new information on how to configure integrated endpoints.

This line:
ctrl = PCI_PTM_CTRL_ENABLE | PCI_PTM_CTRL_ROOT;

should also set the responder capable bit (7.32.2):
If PTM Root Capable is Set, this bit must be Set to 1b.