Hot reset in downstream direction (RC to EP)

Hot reset in downstream direction (RC to EP)

[Murali Karicheri]

I see that hot reset is something the RC port initiate to have EP reset
through link management.

==========================================================================
PCIe reset sequences – The PCI Express protocol specifies a hot reset
mechanism, where downstream components reset through link notification.
Root ports should validate that this mechanism can be applied and the 
hot reset indication is properly detected by a remote device.
Endpoint applications should determine the level of chip reset desired
in case of hot reset detection on the link to validate proper functionality. 
===========================================================================

Does this happen during the enumeration? As this goes in in band, the EP's
link should be up. Can someone tell me what are the triggering points for
this from RC to EP? Does Linux RC support this? It is supposed to a bit
in RC's bridge configuration space that triggers this reset.

-- 
Murali Karicheri
Linux Kernel, Keystone

Re: Hot reset in downstream direction (RC to EP)

[L H]

I've never observed a hot reset during enumeration.  One of the
possible triggers for the RC to issue a hot reset is after receipt of
a fatal AER message (assuming AER is enabled).

Lance

On Fri, Apr 8, 2016 at 4:51 PM, Murali Karicheri <m-karicheri2@ti.com> wrote:
> I see that hot reset is something the RC port initiate to have EP reset
> through link management.
>
> ==========================================================================
> PCIe reset sequences – The PCI Express protocol specifies a hot reset
> mechanism, where downstream components reset through link notification.
> Root ports should validate that this mechanism can be applied and the
> hot reset indication is properly detected by a remote device.
> Endpoint applications should determine the level of chip reset desired
> in case of hot reset detection on the link to validate proper functionality.
> ===========================================================================
>
> Does this happen during the enumeration? As this goes in in band, the EP's
> link should be up. Can someone tell me what are the triggering points for
> this from RC to EP? Does Linux RC support this? It is supposed to a bit
> in RC's bridge configuration space that triggers this reset.
>
> --
> Murali Karicheri
> Linux Kernel, Keystone
> --
> To unsubscribe from this list: send the line "unsubscribe linux-pci" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: Hot reset in downstream direction (RC to EP)

[Murali Karicheri]

On 04/12/2016 02:28 PM, L H wrote:
> I've never observed a hot reset during enumeration.  One of the
> possible triggers for the RC to issue a hot reset is after receipt of
> a fatal AER message (assuming AER is enabled).
> 
Lance,

Ok. Thanks for the response.

Murali

> Lance
> 
> On Fri, Apr 8, 2016 at 4:51 PM, Murali Karicheri <m-karicheri2@ti.com> wrote:
>> I see that hot reset is something the RC port initiate to have EP reset
>> through link management.
>>
>> ==========================================================================
>> PCIe reset sequences – The PCI Express protocol specifies a hot reset
>> mechanism, where downstream components reset through link notification.
>> Root ports should validate that this mechanism can be applied and the
>> hot reset indication is properly detected by a remote device.
>> Endpoint applications should determine the level of chip reset desired
>> in case of hot reset detection on the link to validate proper functionality.
>> ===========================================================================
>>
>> Does this happen during the enumeration? As this goes in in band, the EP's
>> link should be up. Can someone tell me what are the triggering points for
>> this from RC to EP? Does Linux RC support this? It is supposed to a bit
>> in RC's bridge configuration space that triggers this reset.
>>
>> --
>> Murali Karicheri
>> Linux Kernel, Keystone
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-pci" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html


-- 
Murali Karicheri
Linux Kernel, Keystone