Re: [PATCH v3 1/1] PCI/ERR: Fix reset logic in pcie_do_recovery() call

From: Kuppuswamy, Sathyanarayanan
Date: Wed Sep 23 2020 - 22:51:08 EST




On 9/23/20 7:16 PM, Sinan Kaya wrote:
On 9/23/2020 10:04 PM, Kuppuswamy, Sathyanarayanan wrote:
AFAIK, DLLSC is a requirement not optional. Why is this not supported by
non-hotplug ports?
Its required for hotplug capable ports. Please check PCIe spec v5.0 sec
6.7.3.3.

The Data Link Layer State Changed event provides an indication that the
state of
the Data Link Layer Link Active bit in the Link Status Register has
changed.
Support for Data Link Layer State Changed events and software
notification of these
events are required for hot-plug capable Downstream Ports.

I see. Can I assume that your system supports DPC?
DPC is supposed to recover the link via dpc_reset_link().
Yes. But the affected device/drivers cleanup during error recovery
is handled by hotplug handler. So we are facing issue when dealing
with non hotplug capable ports.


--
Sathyanarayanan Kuppuswamy
Linux Kernel Developer