Re: [PATCH] PCI: qcom: Disable halting feature

[Xilin Wu]

On 10/9/2026 8:55 PM, Krishna Chaitanya Chundru wrote:
> The PARF write, read and BDF halt features make the controller wait
> for earlier AXI transactions to complete before issuing new ones. This
> is needed on SoCs whose NoC cannot preserve the ordering of inbound
> transactions from the controller.
>
> On newer SoCs, the NoC preserves this ordering on its own. Halting at
> the controller adds no correctness benefit and reduces inbound DMA
> bandwidth.
>
> Add a noc_ensures_ordering flag to struct qcom_pcie_cfg. Clear all
> three halt features on SoCs that set it. Other SoCs keep enabling
> write halt as before.
>
> Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@xxxxxxxxxxxxxxxx>
> ---
> On shikra we should not disable this feature, when respining the shikra
> we need to make sure this is not getting disabled.
> ---
>   drivers/pci/controller/dwc/pcie-qcom.c | 37 +++++++++++++++++++++++++++++++---
>   1 file changed, 34 insertions(+), 3 deletions(-)

Thanks for the patch. It helps to increase NVMe read speed from 2855MB/s 
to 3106MB/s on SC8280XP.

Tested-by: Xilin Wu <sophon@xxxxxxxxx>

--
Best regards,
Xilin Wu <sophon@xxxxxxxxx>