Re: [PATCH] PCI: qcom: Add register dump support for PCIe Link Down events

[Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>]

On 8/19/2026 4:15 PM, Konrad Dybcio wrote:
> On 8/11/26 6:12 PM, Krishna Chaitanya Chundru wrote:
>> When the PCIe link goes down unexpectedly, being able to inspect the
>> state of key controller registers at the time of failure is valuable
>> for root-causing the issue.
> In this current form, does this patch not cause the splats to appear
> for non-fatal linkdowns (e.g. hot-unplug)?
I agree, but there is no way to differentiate, like link down is from the hot
unplug
or actual link down. For actual link down we can use it for debugging.
>> If a storage endpoint is present downstream, the dump is printed
>> directly via dev_err() so it is visible in dmesg immediately, since a
>> devcoredump read from userspace could otherwise race with a storage
>> failure. Otherwise, the buffer is handed to the devcoredump framework
>> so it can be collected from /sys/class/devcoredump/ for offline
>> analysis.
> I think this is a bit too much, a single implementation is enough.
we had a discussion with mani, mani doesn't want to dump these registers
in dmesg, that is why we are using devcoredump. And in case of NVMe or
storage devices and if the rootfs is in that storage, devcoredump may not
work,  that is why we are dumping the regs in dmesg in case of storage
devices.

- Krishna Chaitanya.
>
> Konrad